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In 1952, the United Kingdom became the third country (after the
United States The United States of America (U.S.A. or USA), commonly known as the United States (U.S. or US) or America, is a country Continental United States, primarily located in North America. It consists of 50 U.S. state, states, a Washington, D.C., ...
and the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
) to develop and test
nuclear weapons A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...
, and is one of the five nuclear-weapon states under the
Treaty on the Non-Proliferation of Nuclear Weapons The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is an international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation ...
. The UK initiated a nuclear weapons programme, codenamed
Tube Alloys Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the ...
, during the Second World War. At the Quebec Conference in August 1943, it was merged with the American
Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
. The
British contribution to the Manhattan Project Britain contributed to the Manhattan Project by helping initiate the effort to build the first atomic bombs in the United States during World War II, and helped carry it through to completion in August 1945 by supplying crucial expertise. Foll ...
saw British scientists participate in most of its work. The British government considered nuclear weapons to be a joint discovery, but the American
Atomic Energy Act of 1946 The Atomic Energy Act of 1946 (McMahon Act) determined how the United States would control and manage the nuclear technology it had jointly developed with its World War II allies, the United Kingdom and Canada. Most significantly, the Act ru ...
(McMahon Act) restricted other countries, including the UK, from access to information about nuclear weapons. Fearing the loss of Britain's
great power A great power is a sovereign state that is recognized as having the ability and expertise to exert its influence on a global scale. Great powers characteristically possess military and economic strength, as well as diplomatic and soft power i ...
status, the UK resumed its own project, now codenamed
High Explosive Research High Explosive Research (HER) was the British project to develop atomic bombs independently after the Second World War. This decision was taken by a cabinet sub-committee on 8 January 1947, in response to apprehension of an American return ...
. On 3 October 1952, it detonated an atomic bomb in the
Monte Bello Islands The Montebello Islands, also rendered as the Monte Bello Islands, are an archipelago of around 174 small islands (about 92 of which are named) lying north of Barrow Island and off the Pilbara coast of north-western Australia. The islands ...
in Australia in
Operation Hurricane Operation Hurricane was the first test of a British atomic device. A plutonium implosion device was detonated on 3 October 1952 in Main Bay, Trimouille Island, in the Montebello Islands in Western Australia. With the success of Operation ...
. Eleven more British
nuclear weapons tests in Australia The United Kingdom conducted 12 major nuclear weapons tests in Australia between 1952 and 1957. These explosions occurred at the Montebello Islands, Emu Field and Maralinga. Sites The British conducted testing in the Pacific Ocean at Malden ...
were carried out over the following decade, including seven British nuclear tests at Maralinga in 1956 and 1957. The
British hydrogen bomb programme The British hydrogen bomb programme was the ultimately successful British effort to develop hydrogen bombs between 1952 and 1958. During the early part of the Second World War, Britain had a nuclear weapons project, codenamed Tube Alloys. At the ...
demonstrated Britain's ability to produce
thermonuclear weapon A thermonuclear weapon, fusion weapon or hydrogen bomb (H bomb) is a second-generation nuclear weapon design. Its greater sophistication affords it vastly greater destructive power than first-generation nuclear bombs, a more compact size, a lo ...
s in the
Operation Grapple Operation Grapple was a set of four series of British nuclear weapons tests of early atomic bombs and hydrogen bombs carried out in 1957 and 1958 at Malden Island and Kiritimati (Christmas Island) in the Gilbert and Ellice Islands in the ...
nuclear tests in the Pacific, and led to the amendment of the McMahon Act. Since the 1958 US–UK Mutual Defence Agreement, the US and the UK have cooperated extensively on nuclear security matters. The nuclear
Special Relationship The Special Relationship is a term that is often used to describe the political, social, diplomatic, cultural, economic, legal, environmental, religious, military and historic relations between the United Kingdom and the United States or i ...
between the two countries has involved the exchange of
classified Classified may refer to: General *Classified information, material that a government body deems to be sensitive *Classified advertising or "classifieds" Music *Classified (rapper) (born 1977), Canadian rapper * The Classified, a 1980s American ro ...
scientific data and
fissile material In nuclear engineering, fissile material is material capable of sustaining a nuclear fission chain reaction. By definition, fissile material can sustain a chain reaction with neutrons of thermal energy. The predominant neutron energy may be t ...
s such as
uranium-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exi ...
and
plutonium Plutonium is a radioactive chemical element with the symbol Pu and atomic number 94. It is an actinide metal of silvery-gray appearance that tarnishes when exposed to air, and forms a dull coating when oxidized. The element normally exh ...
. The UK has not had a programme to develop an independent delivery system since the cancellation of the Blue Streak in 1960. Instead, it purchased US delivery systems for UK use, fitting them with warheads designed and manufactured by the UK's
Atomic Weapons Establishment The Atomic Weapons Establishment (AWE) is a United Kingdom Ministry of Defence research facility responsible for the design, manufacture and support of warheads for the UK's nuclear weapons. It is the successor to the Atomic Weapons Research ...
(AWE) and its predecessor. Under the 1963
Polaris Sales Agreement The Polaris Sales Agreement was a treaty between the United States and the United Kingdom which began the UK Polaris programme. The agreement was signed on 6 April 1963. It formally arranged the terms and conditions under which the Polaris mi ...
, the US supplied the UK with Polaris missiles and
nuclear submarine A nuclear submarine is a submarine powered by a nuclear reactor, but not necessarily nuclear-armed. Nuclear submarines have considerable performance advantages over "conventional" (typically diesel-electric) submarines. Nuclear propulsion, ...
technology. The US also supplied the
Royal Air Force The Royal Air Force (RAF) is the United Kingdom's air and space force. It was formed towards the end of the First World War on 1 April 1918, becoming the first independent air force in the world, by regrouping the Royal Flying Corps (RFC) an ...
and
British Army of the Rhine There have been two formations named British Army of the Rhine (BAOR). Both were originally occupation forces in Germany, one after the First World War and the other after the Second World War. Both formations had areas of responsibility located ...
with nuclear weapons under
Project E Project E was a joint project between the United States and the United Kingdom during the Cold War to provide nuclear weapons to the Royal Air Force (RAF) until sufficient British nuclear weapons became available. It was subsequently expanded ...
in the form of aerial bombs, missiles,
depth charge A depth charge is an anti-submarine warfare (ASW) weapon. It is intended to destroy a submarine by being dropped into the water nearby and detonating, subjecting the target to a powerful and destructive hydraulic shock. Most depth charges use h ...
s and artillery shells until 1992. Nuclear-capable American aircraft have been based in the UK since 1949, but the last US nuclear weapons were withdrawn in 2006. In 1982, the Polaris Sales Agreement was amended to allow the UK to purchase
Trident II A trident is a three- pronged spear. It is used for spear fishing and historically as a polearm. The trident is the weapon of Poseidon, or Neptune, the God of the Sea in classical mythology. The trident may occasionally be held by other marine ...
missiles. Since 1998, when the UK decommissioned its tactical WE.177 bombs, the
Trident A trident is a three- pronged spear. It is used for spear fishing and historically as a polearm. The trident is the weapon of Poseidon, or Neptune, the God of the Sea in classical mythology. The trident may occasionally be held by other mar ...
has been the only operational nuclear weapons system in British service. The delivery system consists of four s based at
HMNB Clyde His Majesty's Naval Base, Clyde (HMNB Clyde; also HMS ''Neptune''), primarily sited at Faslane on the Gare Loch, is one of three operating bases in the United Kingdom for the Royal Navy (the others being HMNB Devonport and HMNB Portsmouth). It ...
in Scotland. Each submarine is armed with up to sixteen Trident II missiles, each carrying warheads in up to eight
multiple independently targetable re-entry vehicle A multiple independently targetable reentry vehicle (MIRV) is an exoatmospheric ballistic missile payload containing several warheads, each capable of being aimed to hit a different target. The concept is almost invariably associated with int ...
s (MIRVs). With at least one submarine always on patrol, the ''Vanguards'' perform a
strategic Strategy (from Greek στρατηγία ''stratēgia'', "art of troop leader; office of general, command, generalship") is a general plan to achieve one or more long-term or overall goals under conditions of uncertainty. In the sense of the "art ...
deterrence role and also have a sub-strategic capability.


History


Tube Alloys

The
neutron The neutron is a subatomic particle, symbol or , which has a neutral (not positive or negative) charge, and a mass slightly greater than that of a proton. Protons and neutrons constitute the atomic nucleus, nuclei of atoms. Since protons and ...
was discovered by
James Chadwick Sir James Chadwick, (20 October 1891 – 24 July 1974) was an English physicist who was awarded the 1935 Nobel Prize in Physics for his discovery of the neutron in 1932. In 1941, he wrote the final draft of the MAUD Report, which inspi ...
at the
Cavendish Laboratory The Cavendish Laboratory is the Department of Physics at the University of Cambridge, and is part of the School of Physical Sciences. The laboratory was opened in 1874 on the New Museums Site as a laboratory for experimental physics and is named ...
at the
University of Cambridge , mottoeng = Literal: From here, light and sacred draughts. Non literal: From this place, we gain enlightenment and precious knowledge. , established = , other_name = The Chancellor, Masters and Schola ...
in February 1932, and in April 1932, his Cavendish colleagues John Cockcroft and
Ernest Walton Ernest Thomas Sinton Walton (6 October 1903 – 25 June 1995) was an Irish physicist and Nobel laureate. He is best known for his work with John Cockcroft to construct one of the earliest types of particle accelerator, the Cockcroft–Walton ...
split
lithium Lithium (from el, λίθος, lithos, lit=stone) is a chemical element with the symbol Li and atomic number 3. It is a soft, silvery-white alkali metal. Under standard conditions, it is the least dense metal and the least dense soli ...
atoms with accelerated
proton A proton is a stable subatomic particle, symbol , H+, or 1H+ with a positive electric charge of +1 ''e'' elementary charge. Its mass is slightly less than that of a neutron and 1,836 times the mass of an electron (the proton–electron mass ...
s. In December 1938,
Otto Hahn Otto Hahn (; 8 March 1879 – 28 July 1968) was a German chemist who was a pioneer in the fields of radioactivity and radiochemistry. He is referred to as the father of nuclear chemistry and father of nuclear fission. Hahn and Lise Meitner ...
and
Fritz Strassmann Friedrich Wilhelm Strassmann (; 22 February 1902 – 22 April 1980) was a German chemist who, with Otto Hahn in December 1938, identified the element barium as a product of the bombardment of uranium with neutrons. Their observation was the ke ...
at Hahn's laboratory in
Berlin-Dahlem Dahlem ( or ) is a locality of the Steglitz-Zehlendorf borough in southwestern Berlin. Until Berlin's 2001 administrative reform it was a part of the former borough of Zehlendorf. It is located between the mansion settlements of Grunewald and ...
bombarded
uranium Uranium is a chemical element with the symbol U and atomic number 92. It is a silvery-grey metal in the actinide series of the periodic table. A uranium atom has 92 protons and 92 electrons, of which 6 are valence electrons. Uranium is weak ...
with slow neutrons, and discovered that
barium Barium is a chemical element with the symbol Ba and atomic number 56. It is the fifth element in group 2 and is a soft, silvery alkaline earth metal. Because of its high chemical reactivity, barium is never found in nature as a free element. Th ...
had been produced. Hahn wrote to his colleague
Lise Meitner Elise Meitner ( , ; 7 November 1878 – 27 October 1968) was an Austrian-Swedish physicist who was one of those responsible for the discovery of the element protactinium and nuclear fission. While working at the Kaiser Wilhelm Institute on r ...
, who, with her nephew
Otto Frisch Otto Robert Frisch FRS (1 October 1904 – 22 September 1979) was an Austrian-born British physicist who worked on nuclear physics. With Lise Meitner he advanced the first theoretical explanation of nuclear fission (coining the term) and first ...
, determined that the uranium
nucleus Nucleus ( : nuclei) is a Latin word for the seed inside a fruit. It most often refers to: * Atomic nucleus, the very dense central region of an atom *Cell nucleus, a central organelle of a eukaryotic cell, containing most of the cell's DNA Nucl ...
had been split, a conclusion they published in ''
Nature Nature, in the broadest sense, is the physical world or universe. "Nature" can refer to the phenomena of the physical world, and also to life in general. The study of nature is a large, if not the only, part of science. Although humans are ...
'' in 1939. By analogy with the division of biological cells, they named the process " fission". The discovery of fission raised the possibility that an extremely powerful
atomic bomb A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bomb ...
could be created. The term was already familiar to the British public through the writings of H. G. Wells, with a continuously exploding bomb in his 1913 novel '' The World Set Free''.
George Paget Thomson Sir George Paget Thomson, FRS (; 3 May 189210 September 1975) was a British physicist and Nobel laureate in physics recognized for his discovery of the wave properties of the electron by electron diffraction. Education and early life Thomson ...
, at
Imperial College London Imperial College London (legally Imperial College of Science, Technology and Medicine) is a public research university in London, United Kingdom. Its history began with Prince Albert, consort of Queen Victoria, who developed his vision for a cu ...
, and Mark Oliphant, an Australian physicist at the
University of Birmingham , mottoeng = Through efforts to heights , established = 1825 – Birmingham School of Medicine and Surgery1836 – Birmingham Royal School of Medicine and Surgery1843 – Queen's College1875 – Mason Science College1898 – Mason Univers ...
, were tasked with carrying out a series of experiments on uranium. Oliphant delegated the task to two German refugee scientists,
Rudolf Peierls Sir Rudolf Ernst Peierls, (; ; 5 June 1907 – 19 September 1995) was a German-born British physicist who played a major role in Tube Alloys, Britain's nuclear weapon programme, as well as the subsequent Manhattan Project, the combined Allie ...
and Frisch, who ironically could not work on the university's secret projects like
radar Radar is a detection system that uses radio waves to determine the distance (''ranging''), angle, and radial velocity of objects relative to the site. It can be used to detect aircraft, Marine radar, ships, spacecraft, guided missiles, motor v ...
because they were
enemy alien In customary international law, an enemy alien is any native, citizen, denizen or subject of any foreign nation or government with which a domestic nation or government is in conflict and who is liable to be apprehended, restrained, secured and ...
s and therefore lacked the necessary security clearance. In March 1940 they calculated the
critical mass In nuclear engineering, a critical mass is the smallest amount of fissile material needed for a sustained nuclear chain reaction. The critical mass of a fissionable material depends upon its nuclear properties (specifically, its nuclear fi ...
of a metallic sphere of pure
uranium-235 Uranium-235 (235U or U-235) is an isotope of uranium making up about 0.72% of natural uranium. Unlike the predominant isotope uranium-238, it is fissile, i.e., it can sustain a nuclear chain reaction. It is the only fissile isotope that exi ...
, and found that instead of tons, as everyone had assumed, as little as would suffice, which would explode with the power of thousands of tons of dynamite. Oliphant took the resulting
Frisch–Peierls memorandum The Frisch–Peierls memorandum was the first technical exposition of a practical nuclear weapon. It was written by expatriate German-Jewish physicists Otto Frisch and Rudolf Peierls in March 1940 while they were both working for Mark Oliphant a ...
to Sir Henry Tizard, the chairman of the Tizard Committee, and the
MAUD Committee The MAUD Committee was a British scientific working group formed during the Second World War. It was established to perform the research required to determine if an atomic bomb was feasible. The name MAUD came from a strange line in a telegram fro ...
was established to investigate further. It held its first meeting on 10 April 1940, in the ground-floor main committee room of the
Royal Society The Royal Society, formally The Royal Society of London for Improving Natural Knowledge, is a learned society and the United Kingdom's national academy of sciences. The society fulfils a number of roles: promoting science and its benefits, re ...
in
Burlington House Burlington House is a building on Piccadilly in Mayfair, London. It was originally a private Neo-Palladian mansion owned by the Earls of Burlington and was expanded in the mid-19th century after being purchased by the British government. To ...
in London. It directed an intensive research effort, and in July 1941, produced two comprehensive reports that reached the conclusion that an atomic bomb was not only technically feasible, but could be produced before the war ended, perhaps in as little as two years. The Committee unanimously recommended pursuing the development of an atomic bomb as a matter of urgency, although it recognised that the resources required might be beyond those available to Britain. A new directorate known as
Tube Alloys Tube Alloys was the research and development programme authorised by the United Kingdom, with participation from Canada, to develop nuclear weapons during the Second World War. Starting before the Manhattan Project in the United States, the ...
was created to coordinate this effort. Sir John Anderson, the
Lord President of the Council The lord president of the Council is the presiding officer of the Privy Council of the United Kingdom and the fourth of the Great Officers of State, ranking below the Lord High Treasurer but above the Lord Keeper of the Privy Seal. The Lord ...
, became the minister responsible, and Wallace Akers from
Imperial Chemical Industries Imperial Chemical Industries (ICI) was a British chemical company. It was, for much of its history, the largest manufacturer in Britain. It was formed by the merger of four leading British chemical companies in 1926. Its headquarters were at ...
(ICI) was appointed the director of Tube Alloys.


Manhattan Project

In July 1940, Britain had offered to give the United States access to its scientific research, and the
Tizard Mission The Tizard Mission, officially the British Technical and Scientific Mission, was a British delegation that visited the United States during WWII to obtain the industrial resources to exploit the military potential of the research and development ( ...
's John Cockcroft briefed American scientists on British developments. He discovered that the American S-1 Project (later renamed the
Manhattan Project The Manhattan Project was a research and development undertaking during World War II that produced the first nuclear weapons. It was led by the United States with the support of the United Kingdom and Canada. From 1942 to 1946, the project w ...
) was smaller than the British, and not as far advanced. The British and American projects exchanged information, but did not initially combine their efforts. British officials did not reply to an August 1941 American offer to create a combined project. In November 1941,
Frederick L. Hovde Frederick Lawson Hovde (7 February 1908 – 1 March 1983) was an American chemical engineer, researcher, educator and president of Purdue University. Born in Erie, Pennsylvania, Hovde received his Bachelor of Chemical Engineering from the Unive ...
, the head of the London liaison office of the American
Office of Scientific Research and Development The Office of Scientific Research and Development (OSRD) was an agency of the United States federal government created to coordinate scientific research for military purposes during World War II. Arrangements were made for its creation during May 1 ...
(OSRD), raised the issue of cooperation and exchange of information with Anderson and
Lord Cherwell Frederick Alexander Lindemann, 1st Viscount Cherwell, ( ; 5 April 18863 July 1957) was a British physicist who was prime scientific adviser to Winston Churchill in World War II. Lindemann was a brilliant intellectual, who cut through bureau ...
, who demurred, ostensibly over concerns about American security. Ironically, it was the British project that had already been penetrated by
atomic spies Atomic spies or atom spies were people in the United States, the United Kingdom, and Canada who are known to have illicitly given information about nuclear weapons production or design to the Soviet Union during World War II and the early ...
for the
Soviet Union The Soviet Union,. officially the Union of Soviet Socialist Republics. (USSR),. was a transcontinental country that spanned much of Eurasia from 1922 to 1991. A flagship communist state, it was nominally a federal union of fifteen nationa ...
. The United Kingdom did not have the manpower or resources of the United States, and despite its early and promising start, Tube Alloys fell behind its American counterpart and was dwarfed by it. On 30 July 1942, Anderson advised the
Prime Minister of the United Kingdom The prime minister of the United Kingdom is the head of government of the United Kingdom. The prime minister advises the sovereign on the exercise of much of the royal prerogative, chairs the Cabinet and selects its ministers. As modern p ...
,
Winston Churchill Sir Winston Leonard Spencer Churchill (30 November 187424 January 1965) was a British statesman, soldier, and writer who served as Prime Minister of the United Kingdom twice, from 1940 to 1945 during the Second World War, and again from ...
, saying: "We must face the fact that ... urpioneering work ... is a dwindling asset and that, unless we capitalise it quickly, we shall be outstripped. We now have a real contribution to make to a 'merger.' Soon we shall have little or none." The British considered producing an atomic bomb without American help, but it would require overwhelming priority, would disrupt to other wartime projects, and was unlikely to be ready in time to affect the outcome of the war in Europe. The unanimous response was that before embarking on this, another effort should be made to secure American cooperation. At the Quebec Conference in August 1943, Churchill and the
President of the United States The president of the United States (POTUS) is the head of state and head of government of the United States of America. The president directs the Federal government of the United States#Executive branch, executive branch of the Federal gove ...
,
Franklin Roosevelt Franklin Delano Roosevelt (; ; January 30, 1882April 12, 1945), often referred to by his initials FDR, was an American politician and attorney who served as the 32nd president of the United States from 1933 until his death in 1945. As the ...
, signed the
Quebec Agreement The Quebec Agreement was a secret agreement between the United Kingdom and the United States outlining the terms for the coordinated development of the science and engineering related to nuclear energy and specifically nuclear weapons. It was ...
, which merged the two national projects. The Quebec Agreement established the
Combined Policy Committee The Quebec Agreement was a secret agreement between the United Kingdom and the United States outlining the terms for the coordinated development of the science and engineering related to nuclear energy and specifically nuclear weapons. It was ...
and the
Combined Development Trust The Combined Development Agency (CDA), originally the Combined Development Trust (CDT), was a defense purchasing authority established in 1944 by the governments of the United States and the United Kingdom. Its role was to ensure adequate supplies ...
to coordinate their efforts, and specified that the weapons could only be used if both the US and UK governments agreed. The 19 September 1944 Hyde Park Agreement extended both commercial and military cooperation into the post-war period. A British mission led by Akers assisted in the development of gaseous diffusion technology at the
SAM Laboratories K-25 was the codename given by the Manhattan Project to the program to produce enriched uranium for atomic bombs using the gaseous diffusion method. Originally the codename for the product, over time it came to refer to the project, the produ ...
in New York. Another, led by Oliphant, who acted as deputy director at the
Berkeley Radiation Laboratory Lawrence Berkeley National Laboratory (LBNL), commonly referred to as the Berkeley Lab, is a United States national laboratory that is owned by, and conducts scientific research on behalf of, the United States Department of Energy. Located in ...
, assisted with the electromagnetic separation process. Cockcroft became the director of the Anglo-Canadian Montreal Laboratory. The British mission to the
Los Alamos Laboratory The Los Alamos Laboratory, also known as Project Y, was a secret laboratory established by the Manhattan Project and operated by the University of California during World War II. Its mission was to design and build the first atomic bombs. Ro ...
was headed by Chadwick, and later Peierls. It included distinguished scientists such as Geoffrey Taylor, James Tuck,
Niels Bohr Niels Henrik David Bohr (; 7 October 1885 – 18 November 1962) was a Danish physicist who made foundational contributions to understanding atomic structure and quantum theory, for which he received the Nobel Prize in Physics in 1922 ...
,
William Penney William George Penney, Baron Penney, (24 June 19093 March 1991) was an English mathematician and professor of mathematical physics at the Imperial College London and later the rector of Imperial College London. He had a leading role in the ...
, Frisch,
Ernest Titterton Sir Ernest William Titterton (4 March 1916 – 8 February 1990) was a British nuclear physicist. A graduate of the University of Birmingham, Titterton worked in a research position under Mark Oliphant, who recruited him to work on radar ...
and
Klaus Fuchs Klaus Emil Julius Fuchs (29 December 1911 – 28 January 1988) was a German theoretical physicist and atomic spy who supplied information from the American, British and Canadian Manhattan Project to the Soviet Union during and shortly af ...
, who was later revealed to be a Soviet spy. As overall head of the British Mission, Chadwick forged a close and successful partnership with
Brigadier General Brigadier general or Brigade general is a military rank used in many countries. It is the lowest ranking general officer in some countries. The rank is usually above a colonel, and below a major general or divisional general. When appointe ...
Leslie R. Groves, the director of the Manhattan Project. He ensured that British participation was complete and wholehearted. Penney worked on means to assess the effects of a nuclear explosion, and wrote a paper on what height the bombs should be detonated at for maximum effect in attacks on Germany and Japan. He served as a member of the target committee established by Groves to select Japanese cities for atomic bombing, and on
Tinian Tinian ( or ; old Japanese name: 天仁安島, ''Tenian-shima'') is one of the three principal islands of the Commonwealth of the Northern Mariana Islands. Together with uninhabited neighboring Aguiguan, it forms Tinian Municipality, one of the ...
with
Project Alberta Project Alberta, also known as Project A, was a section of the Manhattan Project which assisted in delivering the first nuclear weapons in the atomic bombing of Hiroshima and Nagasaki during World War II. Project Alberta was formed in Marc ...
as a special consultant. Because the Quebec Agreement specified that nuclear weapons would not be used against another country without mutual consent, British authorisation was required for their use. On 4 July 1945, Field Marshal
Henry Maitland Wilson Field Marshal Henry Maitland Wilson, 1st Baron Wilson, (5 September 1881 – 31 December 1964), also known as Jumbo Wilson, was a senior British Army officer of the 20th century. He saw active service in the Second Boer War and then during the ...
agreed that the use of nuclear weapons against Japan would be recorded as a decision of the Combined Policy Committee. Along with
Group Captain Group captain is a senior commissioned rank in the Royal Air Force, where it originated, as well as the air forces of many countries that have historical British influence. It is sometimes used as the English translation of an equivalent rank i ...
Leonard Cheshire Geoffrey Leonard Cheshire, Baron Cheshire, (7 September 1917 – 31 July 1992) was a highly decorated Royal Air Force (RAF) pilot and group captain during the Second World War, and a philanthropist. Among the honours Cheshire received as ...
, sent by Wilson as a British representative, Penney watched the
bombing of Nagasaki The United States detonated two atomic bombs over the Japanese cities of Hiroshima and Nagasaki on 6 and 9 August 1945, respectively. The two bombings killed between 129,000 and 226,000 people, most of whom were civilians, and remain the o ...
from the observation plane '' Big Stink''. He also formed part of the Manhattan Project's post-war scientific mission to Hiroshima and Nagasaki that assessed the extent of the damage caused by the bombs.


End of American cooperation

With the end of the war, the
Special Relationship The Special Relationship is a term that is often used to describe the political, social, diplomatic, cultural, economic, legal, environmental, religious, military and historic relations between the United Kingdom and the United States or i ...
between Britain and the United States "became very much less special". The British government had trusted that America would share nuclear technology, which it considered a joint discovery. On 8 August 1945, the Prime Minister,
Clement Attlee Clement Richard Attlee, 1st Earl Attlee, (3 January 18838 October 1967) was a British politician who served as Prime Minister of the United Kingdom from 1945 to 1951 and Leader of the Labour Party from 1935 to 1955. He was Deputy Prime Mini ...
, sent a message to President
Harry Truman Harry S. Truman (May 8, 1884December 26, 1972) was the 33rd president of the United States, serving from 1945 to 1953. A leader of the Democratic Party, he previously served as the 34th vice president from January to April 1945 under Franklin ...
in which he referred to themselves as "heads of the Governments which have control of this great force". But Roosevelt had died on 12 April 1945, and the Hyde Park Agreement was not binding on subsequent administrations. In fact, it was physically lost. When Wilson raised the matter in a Combined Policy Committee meeting in June, the American copy could not be found. On 9 November 1945, Attlee and the
Prime Minister of Canada The prime minister of Canada (french: premier ministre du Canada, link=no) is the head of government of Canada. Under the Westminster system, the prime minister governs with the confidence of a majority the elected House of Commons; as su ...
,
Mackenzie King William Lyon Mackenzie King (December 17, 1874 – July 22, 1950) was a Canadian statesman and politician who served as the tenth prime minister of Canada for three non-consecutive terms from 1921 to 1926, 1926 to 1930, and 1935 to 1948. A L ...
, went to Washington, D.C., to confer with Truman about future cooperation in nuclear weapons and nuclear power. A Memorandum of Intention they signed replaced the Quebec Agreement. It made Canada a full partner, continued the Combined Policy Committee and Combined Development Trust, and reduced the obligation to obtain consent for the use of nuclear weapons to merely requiring consultation. The three leaders agreed that there would be full and effective cooperation on atomic energy, but British hopes were soon disappointed; Groves restricted cooperation to basic scientific research. The next meeting of the Combined Policy Committee on 15 April 1946 produced no accord on collaboration, and resulted in an exchange of cables between Truman and Attlee. Truman cabled on 20 April that he did not see the communiqué he had signed as obligating the United States to assist Britain in designing, constructing and operating an atomic energy plant. The passing of the
Atomic Energy Act of 1946 The Atomic Energy Act of 1946 (McMahon Act) determined how the United States would control and manage the nuclear technology it had jointly developed with its World War II allies, the United Kingdom and Canada. Most significantly, the Act ru ...
(McMahon Act) in August 1946, which was signed by Truman on 1 August 1946, and went into effect at midnight on 1 January 1947, ended technical cooperation. Its control of "restricted data" prevented the United States' allies from receiving any information. The remaining British scientists working in the United States were denied access to papers that they had written just days before. This partly resulted from the arrest for espionage of British physicist
Alan Nunn May Alan Nunn May (sometimes Allan) (2 May 1911 – 12 January 2003) was a British physicist and a confessed and convicted Soviet spy who supplied secrets of British and American atomic research to the Soviet Union during World War II. Early lif ...
, who had worked in the Montreal Laboratory, in February 1946, while the legislation was being debated. It was but the first of a series of spy scandals. The arrest of Klaus Fuchs in January 1950, and the June 1951 defection of Donald Maclean, who had served as a British member of the Combined Policy Committee from January 1947 to August 1948, left Americans with a distrust of British security arrangements.


Resumption of independent UK efforts

Most leading scientists and politicians of all parties were determined that Britain should have its own nuclear weapons. Their motives included national defence, a vision of a civil programme for nuclear power, and a desire that a British voice should be as powerful as any in international debate. Attlee set up a cabinet sub-committee, the Gen 75 Committee (known informally by Attlee as the "Atomic Bomb Committee"), on 10 August 1945 to examine the feasibility of an independent British nuclear weapons programme. A
nuclear reactor A nuclear reactor is a device used to initiate and control a fission nuclear chain reaction or nuclear fusion reactions. Nuclear reactors are used at nuclear power plants for electricity generation and in nuclear marine propulsion. Heat fr ...
and plutonium-processing facility was approved by the Gen 75 committee on 18 December 1945 "with the highest urgency and importance". The
Chiefs of Staff Committee The Chiefs of Staff Committee (CSC) is composed of the most senior military personnel in the British Armed Forces who advise on operational military matters and the preparation and conduct of military operations. The committee consists of the ...
considered the issue in July 1946, and recommended that Britain acquire nuclear weapons. They estimated that 200 bombs would be required by 1957. The Tube Alloys Directorate was transferred from the
Department of Scientific and Industrial Research Department of Scientific and Industrial Research, abbreviated DSIR was the name of several British Empire organisations founded after the 1923 Imperial Conference to foster intra-Empire trade and development. * Department of Scientific and Industria ...
to the Ministry of Supply effective 1 November 1945. To coordinate the atomic energy effort, Marshal of the Royal Air Force Lord Portal, the wartime Chief of the Air Staff, was appointed the Controller of Production, Atomic Energy (CPAE) in March 1946. The Gen 75 Committee considered the proposal in October 1946. In October 1946, Attlee called a meeting to discuss building a gaseous diffusion plant for
uranium enrichment Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238 ...
. Michael Perrin, who was present, later recalled that: The decision to proceed was formally made on 8 January 1947 at a meeting of Gen 163, a subcommittee of the Gen 75 Committee consisting of six
Cabinet Cabinet or The Cabinet may refer to: Furniture * Cabinetry, a box-shaped piece of furniture with doors and/or drawers * Display cabinet, a piece of furniture with one or more transparent glass sheets or transparent polycarbonate sheets * Filin ...
members, including Attlee, and was publicly announced in the
House of Commons The House of Commons is the name for the elected lower house of the bicameral parliaments of the United Kingdom and Canada. In both of these countries, the Commons holds much more legislative power than the nominally upper house of parliament. T ...
on 12 May 1948. D notice No. 25 prohibited the publication of details on the design, construction or location of atomic weapons. The project was given the cover name "High Explosive Research". As Chief Superintendent Armament Research (CSAR, pronounced "Caesar"), Penney directed bomb design from Fort Halstead. In 1951, his design group moved to a new site at
Aldermaston Aldermaston is a village and civil parish in Berkshire, England. In the 2011 Census, the parish had a population of 1015. The village is in the Kennet Valley and bounds Hampshire to the south. It is approximately from Newbury, Basingstok ...
in Berkshire. Production facilities were constructed under the direction of Christopher Hinton, who established his headquarters in a former
Royal Ordnance Factory Royal Ordnance Factories (ROFs) was the collective name of the UK government's munitions factories during and after the Second World War. Until privatisation, in 1987, they were the responsibility of the Ministry of Supply, and later the Mini ...
(ROF) at ROF Risley in
Lancashire Lancashire ( , ; abbreviated Lancs) is the name of a historic county, ceremonial county, and non-metropolitan county in North West England. The boundaries of these three areas differ significantly. The non-metropolitan county of Lancas ...
. These included a uranium metal plant at Springfields, nuclear reactors and a plutonium processing plant at Windscale, and a gaseous diffusion uranium enrichment facility at
Capenhurst Capenhurst is a village and civil parish in Chester in the unitary authority of Cheshire West and Chester and the ceremonial county of Cheshire England. According to the 2001 Census, Capenhurst had a population of 237, increasing to 380 at the 2 ...
, near
Chester Chester is a cathedral city and the county town of Cheshire, England. It is located on the River Dee, close to the English–Welsh border. With a population of 79,645 in 2011,"2011 Census results: People and Population Profile: Chester Loca ...
. The two Windscale reactors became operational in October 1950 and June 1951. The gaseous diffusion plant at Capenhurst began producing
highly enriched uranium Enriched uranium is a type of uranium in which the percent composition of uranium-235 (written 235U) has been increased through the process of isotope separation. Naturally occurring uranium is composed of three major isotopes: uranium-238 (238U ...
in 1954. Uranium ore was stockpiled at Springfields. As the American nuclear programme expanded, its requirements became greater than the production of the existing mines. To gain access to the stockpile, they reopened negotiations in 1947. This resulted in the 1948 ''
Modus Vivendi ''Modus vivendi'' (plural ''modi vivendi'') is a Latin phrase that means "mode of living" or " way of life". It often is used to mean an arrangement or agreement that allows conflicting parties to coexist in peace. In science, it is used to descr ...
'', which allowed for consultation on the use of nuclear weapons, and limited sharing of technical information between the United States, Britain and Canada.


Unsuccessful attempt to renew American partnership

The United States feared the USSR obtaining British atomic technology after conquering the United Kingdom in an invasion of western Europe. In February 1949 General Dwight D. Eisenhower offered to General Sir
William Duthie Morgan General Sir William Duthie Morgan, (15 December 1891 – 13 May 1977) was a British Army officer. During the Second World War, he commanded the Mediterranean Theatre of Operations during the late stage of the war. Early life and military career ...
American atomic weapons if the British programme ended. Britain would have used the weapons with its own aircraft for its own targets. Whether the McMahon Act would have permitted the transaction is unclear, but Britain refused because of its intention to develop its own weapons. By that year, international control of atomic weapons seemed almost impossible to achieve, and Truman proposed to the Joint Committee on Atomic Energy in July a "full partnership" with Britain in exchange for uranium; negotiations between the two countries began that month. While the first Soviet atomic bomb test in August 1949 was embarrassing to the British (who had not expected a Soviet atomic weapon until 1954) for having been beaten, it was for the Americans another reason for cooperation. Although they would soon have their own nuclear capability, the British proposed that instead of building their own uranium-enrichment plant they would send most of their scientists to work in the US, and swap plutonium from Windscale for enriched uranium from the US. While Britain would not formally give up building or researching its own weapons, the US would manufacture all the bombs and allocate some to Britain. By agreeing to subsume its own weapons programme within the American one, the plan would have given Britain nuclear weapons much sooner than its own target date of late 1952. Although Truman supported the proposal, several key officials, including the
United States Atomic Energy Commission The United States Atomic Energy Commission (AEC) was an agency of the United States government established after World War II by U.S. Congress to foster and control the peacetime development of atomic science and technology. President ...
's Lewis Strauss and Senator
Arthur Vandenberg Arthur Hendrick Vandenberg Sr. (March 22, 1884April 18, 1951) was an American politician who served as a United States senator from Michigan from 1928 to 1951. A member of the Republican Party, he participated in the creation of the United Natio ...
, did not. Their opposition, along with security concerns raised by the arrest of Fuchs, who was working at Harwell, ended the negotiations in January 1950. After Britain developed nuclear weapons through its own efforts, the engineer Sir Leonard Owen stated that "the McMahon Act was probably one of the best things that happened ... as it made us work and think for ourselves along independent lines."


First test and early systems

Churchill, now again prime minister, announced on 17 February 1952 that the first British weapon test would occur before the end of the year. During
Operation Hurricane Operation Hurricane was the first test of a British atomic device. A plutonium implosion device was detonated on 3 October 1952 in Main Bay, Trimouille Island, in the Montebello Islands in Western Australia. With the success of Operation ...
, an atomic bomb was detonated on board the
frigate A frigate () is a type of warship. In different eras, the roles and capabilities of ships classified as frigates have varied somewhat. The name frigate in the 17th to early 18th centuries was given to any full-rigged ship built for speed an ...
anchored in a lagoon in the
Monte Bello Islands The Montebello Islands, also rendered as the Monte Bello Islands, are an archipelago of around 174 small islands (about 92 of which are named) lying north of Barrow Island and off the Pilbara coast of north-western Australia. The islands ...
in
Western Australia Western Australia (commonly abbreviated as WA) is a state of Australia occupying the western percent of the land area of Australia excluding external territories. It is bounded by the Indian Ocean to the north and west, the Southern Ocean to t ...
on 3 October 1952. Britain thereby became the third country to develop and test nuclear weapons. This led to the development of the first deployed weapon, the Blue Danube free-fall bomb. It had a diameter, 32
explosive lens An explosive lens—as used, for example, in nuclear weapons—is a highly specialized shaped charge. In general, it is a device composed of several explosive charges. These charges are arranged and formed with the intent to control the shape ...
implosion system with a levitated pit suspended within a natural uranium tamper. The warhead was contained within a bomb casing measuring diameter and long, and it weighed approximately , of which about was high explosive. The first Blue Danube bombs were delivered to the Royal Air Force (RAF) Bomber Command in November 1953, although the bombers to deliver them did not become available until 1955. On 11 October 1956, a
Vickers Valiant The Vickers Valiant was a British high-altitude jet bomber designed to carry nuclear weapons, and in the 1950s and 1960s was part of the Royal Air Force's " V bomber" strategic deterrent force. It was developed by Vickers-Armstrongs in respon ...
from
No. 49 Squadron RAF No. 49 Squadron was a bomber squadron of the Royal Air Force from 1938 to 1965. They were the first squadron to receive the Hampden in September 1938. The unit achieved fame through the Victoria Cross awarded to Rod Learoyd in 1940 and for its r ...
piloted by Edwin Flavell became the first British aircraft to drop a live atomic bomb when a Blue Danube was exploded over
Maralinga, South Australia Maralinga, in the remote western areas of South Australia, was the site, measuring about in area, of British nuclear tests in the mid-1950s. In January 1985 native title was granted to the Maralinga Tjarutja, a southern Pitjantjatjara Aborigi ...
during Operation Buffalo. About fifty-eight Blue Danube bombs were produced. The first bombs had plutonium cores, but all service models were modified to use a composite core which used both uranium-235 and plutonium. The bomb had a nominal yield of . The cores were stored separately from the high explosive components in concrete "igloos" at
RAF Barnham RAF Barnham (also called Barnham Camp) is a Royal Air Force station situated in the English county of Suffolk south of the Norfolk town of Thetford. It is located to the north of the village of Barnham on Thetford Heaths. The camp is a sat ...
in
Suffolk Suffolk () is a ceremonial county of England in East Anglia. It borders Norfolk to the north, Cambridgeshire to the west and Essex to the south; the North Sea lies to the east. The county town is Ipswich; other important towns include ...
and RAF Faldingworth in
Lincolnshire Lincolnshire (abbreviated Lincs.) is a Counties of England, county in the East Midlands of England, with a long coastline on the North Sea to the east. It borders Norfolk to the south-east, Cambridgeshire to the south, Rutland to the south-we ...
. Some casings were stored elsewhere in the UK and in Cyprus for "second strike" use. It remained in service until 1962, and was replaced by
Red Beard is a 1965 Japanese ''jidaigeki'' film co-written, edited, and directed by Akira Kurosawa, in his last collaboration with actor Toshiro Mifune. Based on Shūgorō Yamamoto's 1959 short story collection, '' Akahige Shinryōtan'', the film takes pl ...
, a smaller tactical nuclear weapon. The Blue Danube cores were recycled, and the plutonium used in other nuclear weapons. Being so big and heavy, Blue Danube could only be carried by the V bombers, so-called because they all had names starting with a "V". The three strategic bombers, known collectively as the V class, comprised the United Kingdom's strategic nuclear strike force during the 1950s and 1960s, which was known as V force of the Main Force. The three V bombers were the
Vickers Valiant The Vickers Valiant was a British high-altitude jet bomber designed to carry nuclear weapons, and in the 1950s and 1960s was part of the Royal Air Force's " V bomber" strategic deterrent force. It was developed by Vickers-Armstrongs in respon ...
, which entered service in February 1955; the
Avro Vulcan The Avro Vulcan (later Hawker Siddeley Vulcan from July 1963) is a jet-powered, tailless, delta-wing, high-altitude, strategic bomber, which was operated by the Royal Air Force (RAF) from 1956 until 1984. Aircraft manufacturer A.V. Roe an ...
, which entered service in May 1956; and the
Handley Page Victor The Handley Page Victor is a British jet-powered strategic bomber developed and produced by Handley Page during the Cold War. It was the third and final '' V bomber'' to be operated by the Royal Air Force (RAF), the other two being the Avr ...
, which entered service in November 1957. The V Bomber force reached its peak in June 1964, when 50 Valiants, 70 Vulcans and 39 Victors were in service.


Thermonuclear development

A month after Britain's first atomic weapons test, America tested the first thermonuclear (hydrogen) bomb. The Soviets responded with
Joe 4 Joe 4 was an American nickname for the first Soviet test of a thermonuclear weapon on August 12, 1953, that detonated with a force equivalent to 400 kilotons of TNT. The proper Soviet terminology for the warhead was RDS-6s, , . RDS-6 utilized ...
, a
boosted fission weapon A boosted fission weapon usually refers to a type of nuclear bomb that uses a small amount of fusion fuel to increase the rate, and thus yield, of a fission reaction. The neutrons released by the fusion reactions add to the neutrons released ...
, in 1953. Penney feared that Britain could not afford to develop a hydrogen bomb, as did Tizard, who argued that the nation should focus on conventional forces instead of duplicating the nuclear capabilities of the American forces that were already defending Britain and Europe. He warned that: "We are a great nation, but if we continue to behave like a Great Power we shall soon cease to be a great nation. Let us take warning from the fate of the Great Powers of the past and not burst ourselves with pride." The government decided on 27 July 1954 to begin development of a thermonuclear bomb, and announced its plans in February 1955. British knowledge of thermonuclear weapons was based on the work done at the Los Alamos Laboratory during the war. Two British scientists, Egon Bretscher and Klaus Fuchs, had attended the conference there on the Super (as it was then called) in April 1946, and Chadwick had written a secret report on it in May 1946, but the design was found to be unworkable. Some intelligence about Joe 4 was derived from its debris, which was provided to Britain under the 1948 ''Modus Vivendi''. Penney established three megaton bomb projects at Aldermaston: Orange Herald, a large boosted fission weapon; Green Bamboo, an interim thermonuclear design similar to the Soviet Layer Cake used in Joe 4 and the American Alarm Clock; and Green Granite, a true thermonuclear design. The Green Granite prototype, known as Short Granite, was tested in the first of the
Operation Grapple Operation Grapple was a set of four series of British nuclear weapons tests of early atomic bombs and hydrogen bombs carried out in 1957 and 1958 at Malden Island and Kiritimati (Christmas Island) in the Gilbert and Ellice Islands in the ...
test series, Grapple 1. The bomb was dropped from a height of by a Vickers Valiant piloted by Wing Commander Kenneth Hubbard, off the shore of
Malden Island Malden Island, sometimes called Independence Island in the 19th century, is a low, arid, uninhabited atoll in the central Pacific Ocean, about in area. It is one of the Line Islands belonging to the Republic of Kiribati. The lagoon is enti ...
in the Pacific on 15 May 1957. It was Britain's second airdrop of a nuclear bomb after the Operation Buffalo test at Maralinga on 11 October 1956, and the first of a thermonuclear weapon. The United States had not attempted an airdrop of a hydrogen bomb until the
Operation Redwing Operation Redwing was a United States series of 17 nuclear test detonations from May to July 1956. They were conducted at Bikini and Enewetak atolls by Joint Task Force 7 (JTF7).Blumenson, Martin and Hugh D. Hexamer (1956). ''A History of ...
Cherokee test on 21 May 1956. Short Granite's yield was estimated at , far below its designed capability. Despite its failure, the test was hailed as a successful thermonuclear explosion, and the government did not confirm or deny reports that the UK had become a third thermonuclear power. When documents on the series began to be declassified in the 1990s, the Grapple X tests were denounced as a hoax. The reports would not have fooled the American observers into thinking they were thermonuclear explosions, as they were involved in their analysis. The next test was Grapple 2, of Orange Herald, the first British weapon to incorporate an external neutron initiator. It was dropped on 31 May, and exploded with a force of . The yield was the largest ever achieved by a single stage device, which made it technically a megaton weapon. The bomb was hailed as a hydrogen bomb, and the truth that it was actually a large fission bomb was kept secret by the British government until the end of the
Cold War The Cold War is a term commonly used to refer to a period of geopolitical tension between the United States and the Soviet Union and their respective allies, the Western Bloc and the Eastern Bloc. The term '' cold war'' is used because t ...
. Penney cancelled the planned Green Granite test, and substituted Purple Granite, a Short Granite with some minor modifications. Its yield was a very disappointing , even less than Short Granite; the changes had not worked. An
Operational Requirement An Operational Requirement, commonly abbreviated OR, was a United Kingdom (UK) Air Ministry document setting out the required characteristics for a future (i.e., as-yet unbuilt) military aircraft or weapon system. The numbered OR would describe ...
(OR1142) was issued in 1955 for a thermonuclear warhead for a
medium-range ballistic missile A medium-range ballistic missile (MRBM) is a type of ballistic missile with medium range, this last classification depending on the standards of certain organizations. Within the U.S. Department of Defense, a medium-range missile is defined b ...
, which became Blue Streak. This was revised in November 1955, with "megaton" replacing "thermonuclear". Orange Herald could then meet the requirement. Codenamed Green Grass, the unsuccessful fusion boosting was omitted, and it used Green Bamboo's 72-lens implosion system instead of Orange Herald's 32. This allowed the amount of highly enriched uranium to be reduced from 120 to 75 kg. Its yield was estimated at . For use in the V bombers, it was placed in a Blue Danube casing to become
Violet Club Violet may refer to: Common meanings * Violet (color), a spectral color with wavelengths shorter than blue * One of a list of plants known as violet, particularly: ** ''Viola'' (plant), a genus of flowering plants Places United States * Vio ...
. Road transport of the weapon was hazardous. As a safety measure 120,000 steel ball bearings were used to fill a cavity inside the core and keep the fissile components apart. In an accident, the steel bung was removed and the ball bearings spilled on the floor of an aircraft hangar, leaving the bomb armed and dangerous. About ten were delivered. The scientists at Aldermaston had not yet mastered the design of thermonuclear weapons. They produced a new design, called Round A. Another trial was scheduled, known as Grapple X. Round A was dropped on 8 November 1957. To save time and money, the target was off the southern tip of Christmas Island rather than off Malden Island, just from the airfield where 3,000 men were based. This time the yield of exceeded expectations. Round A was a true hydrogen bomb, but it used a relatively large quantity of expensive highly enriched uranium. Aldermaston had plenty of ideas about how to follow up Grapple X. A new design used
lithium deuteride Lithium hydride is an inorganic compound with the formula Li H. This alkali metal hydride is a colorless solid, although commercial samples are grey. Characteristic of a salt-like (ionic) hydride, it has a high melting point, and it is not solub ...
that was less enriched in
lithium-6 Naturally occurring lithium (3Li) is composed of two stable isotopes, lithium-6 and lithium-7, with the latter being far more abundant on Earth. Both of the natural isotopes have an unexpectedly low nuclear binding energy per nucleon ( for l ...
(and therefore had more lithium-7), but more of it, thereby reducing the amount of uranium-235 in the core. Because of the possibility of an international moratorium on atmospheric testing, plans for the trial, codenamed Grapple Y, were given verbal approval by the Prime Minister, and known only to a handful of officials. The bomb was dropped off Christmas Island on 28 April 1958. It had an explosive yield of about , and remains the largest British nuclear weapon ever tested. The design of Grapple Y was notably successful because much of its yield came from its thermonuclear reaction instead of fission of a uranium-238 tamper, making it a true hydrogen bomb, and because its yield had been correctly predicted—indicating that its designers understood what they were doing. Eisenhower, now US president, on 22 August 1958 announced a moratorium on nuclear testing. This did not mean an immediate end to testing; on the contrary, the United States, the Soviet Union and the United Kingdom all rushed to perform as much testing as possible before the deadline. A new British test series, known as Grapple Z, commenced on 22 August. It explored new technologies such as the use of external neutron initiators, which had first been tried out with Orange Herald. Core boosting using
tritium Tritium ( or , ) or hydrogen-3 (symbol T or H) is a rare and radioactive isotope of hydrogen with half-life about 12 years. The nucleus of tritium (t, sometimes called a ''triton'') contains one proton and two neutrons, whereas the nucleus of ...
and external boosting with layers of lithium deuteride were successfully tested, allowing a smaller, lighter two-stage devices. The international moratorium commenced on 31 October 1958, and Britain ceased atmospheric testing for good.


An independent deterrent

Believing that the United Kingdom was extremely vulnerable to a nuclear attack to which defence was impossible, the Chiefs of Staff and the RAF first advocated a British nuclear deterrence—not just nuclear weapons—in 1945: "It is our opinion that our only chance of securing a quick decision is by launching a devastating attack upon nemy citieswith absolute weapons." In 1947, the Chiefs of Staff stated that even with American help the United Kingdom could not prevent the "vastly superior" Soviet forces from overrunning Western Europe, from which Russia could destroy Britain with missiles without using atomic weapons. Only "the threat of large-scale damage from similar weapons" could prevent the Soviet Union from using atomic weapons in a war.
Air Chief Marshal Air chief marshal (Air Chf Mshl or ACM) is a high-ranking air officer originating from the Royal Air Force. The rank is used by air forces of many countries that have historical British influence. An air chief marshal is equivalent to an Admi ...
Sir
John Slessor Marshal of the Royal Air Force Sir John Cotesworth Slessor, (3 June 1897 – 12 July 1979) was a senior commander in the Royal Air Force (RAF), serving as Chief of the Air Staff from 1950 to 1952. As a pilot in the Royal Flying Corps d ...
, who became Chief of the Air Staff in 1950, wrote that year that the Soviet superiority in European forces was so great that even "an ultimatum by Russia within the next two to three years" might cause Western Europe to surrender without a war. He feared that the United Kingdom might also do so "unless we can make ourselves far less defenceless than we are now." By 1952, the
Air Ministry The Air Ministry was a department of the Government of the United Kingdom with the responsibility of managing the affairs of the Royal Air Force, that existed from 1918 to 1964. It was under the political authority of the Secretary of Stat ...
had abandoned the concept of a conventional defence of Western Europe. The hydrogen bomb increased the threat to Britain. In 1957, a government study stated that although RAF fighters would "unquestionably be able to take a heavy toll of enemy bombers, a proportion would inevitably get through. Even if it were only a dozen, they could with megaton bombs inflict widespread devastation." Although disarmament remained a British goal, "the only existing safeguard against major aggression is the power to threaten retaliation with nuclear weapons." Churchill stated in a 1955 speech that deterrence would be "the parents of disarmament" and that, unless Britain contributed to Western deterrence with its own weapons, during a war the targets that threatened it the most might not be prioritised. The Prime Minister,
Harold Macmillan Maurice Harold Macmillan, 1st Earl of Stockton, (10 February 1894 – 29 December 1986) was a British Conservative statesman and politician who was Prime Minister of the United Kingdom from 1957 to 1963. Caricatured as " Supermac", ...
, advanced the position that nuclear weapons would give Britain influence over targeting and American policy, and would affect strategy in the Middle East and Far East. His Minister of Defence,
Duncan Sandys Edwin Duncan Sandys, Baron Duncan-Sandys (; 24 January 1908 – 26 November 1987), was a British politician and minister in successive Conservative governments in the 1950s and 1960s. He was a son-in-law of Winston Churchill and played a key r ...
, considered that nuclear weapons reduced Britain's dependence on the United States. The 1956
Suez Crisis The Suez Crisis, or the Second Arab–Israeli war, also called the Tripartite Aggression ( ar, العدوان الثلاثي, Al-ʿUdwān aṯ-Ṯulāṯiyy) in the Arab world and the Sinai War in Israel,Also known as the Suez War or 1956 Wa ...
demonstrated that Britain was no longer a great power, but increased the value to Britain of an independent nuclear deterrent that would give it greater influence with the US and USSR. While the military target of British nuclear weapons was the Soviet Union, the political target was the United States. Independent targeting was vital. The Chiefs of Staff believed that—contrary to Tizard's view—once the Soviet Union became able to attack the United States itself with nuclear weapons in the late 1950s, America might not risk its own cities to defend Europe, or not emphasise targets that endangered the United Kingdom more than the United States. Britain thus needed the ability to convince the USSR that attacking Europe would be too costly regardless of American participation. Part of the perceived effectiveness of an independent deterrent was the willingness to target enemy cities. Slessor saw atomic weapons as a way to avoid a third devastating world war given that the two previous ones had begun without them. When Air Marshal Sir George Mills became head of RAF Bomber Command in 1955 he similarly insisted on targeting Soviet cities.


Renewed American partnership

The Soviet Union's launch of
Sputnik 1 Sputnik 1 (; see § Etymology) was the first artificial Earth satellite. It was launched into an elliptical low Earth orbit by the Soviet Union on 4 October 1957 as part of the Soviet space program. It sent a radio signal back to Earth for ...
, the world's first
artificial satellite A satellite or artificial satellite is an object intentionally placed into orbit in outer space. Except for passive satellites, most satellites have an electricity generation system for equipment on board, such as solar panels or radioisoto ...
, on 4 October 1957, came as a tremendous shock to the American public, who had trusted that American technological superiority ensured their invulnerability. Now, suddenly, there was incontrovertible proof that, in some areas at least, the Soviet Union was actually ahead. In the widespread calls for action in response to the
Sputnik crisis The Sputnik crisis was a period of public fear and anxiety in Western Bloc, Western nations about the perceived technological gap between the United States and Soviet Union caused by the Soviets' launch of ''Sputnik 1'', the world's first arti ...
, officials in the United States and Britain seized an opportunity to mend the relationship with Britain that had been damaged by the Suez Crisis. Macmillan wrote to Eisenhower on 10 October urging that the two countries pool their resources to meet the challenge. British information security, or the lack thereof, no longer seemed so important now that the Soviet Union was apparently ahead, and British scientists had demonstrated that they understood how to build a hydrogen bomb with a different form of the Teller-Ulam design to the Americans. The opposition that had derailed previous attempts was now absent. The McMahon Act was amended, paving the way for the 1958 US–UK Mutual Defence Agreement (MDA). Macmillan called this "the Great Prize". Under the MDA, 5.37 tonnes of UK-produced plutonium was sent to the US in exchange for 6.7 kg of tritium and 7.5 tonnes of HEU between 1960 and 1979. Much of the HEU supplied by the US was used not for weapons, but as fuel for the growing fleet of UK
nuclear submarine A nuclear submarine is a submarine powered by a nuclear reactor, but not necessarily nuclear-armed. Nuclear submarines have considerable performance advantages over "conventional" (typically diesel-electric) submarines. Nuclear propulsion, ...
s. Under the MDA, the US supplied the UK with not just nuclear submarine propulsion technology, but a complete S5W pressurised water reactor of the kind used to power the US submarines. This was used in the Royal Navy's first nuclear-powered submarine, , which was launched in 1960 and commissioned in 1963. The S5W had a
nuclear reactor core A nuclear reactor core is the portion of a nuclear reactor containing the nuclear fuel components where the nuclear reactions take place and the heat is generated. Typically, the fuel will be low- enriched uranium contained in thousands of ind ...
that used uranium enriched to between 93 and 97 per cent uranium-235. Reactor technology was transferred from Westinghouse to
Rolls-Royce Rolls-Royce (always hyphenated) may refer to: * Rolls-Royce Limited, a British manufacturer of cars and later aero engines, founded in 1906, now defunct Automobiles * Rolls-Royce Motor Cars, the current car manufacturing company incorporated in ...
, which used it as the basis for its PWR1 reactor used in the UK's nuclear submarines. The MDA has been renewed or amended many times. Most amendments merely extended the treaty for another five or ten years; others added definitions and made minor changes. , the most recent renewal was on 22 July 2014, extending the treaty to 31 December 2024. A 1974 US proliferation report discussing British nuclear and missile development noted that "In many cases, it is based on technology received from the US and could not legitimately be passed on without US permission."


Weapons systems


US nuclear weapons in British service

Production of British nuclear weapons was slow and Britain had only ten atomic bombs on hand in 1955 and just fourteen in 1956. At the three-power Bermuda Conference with Eisenhower in December 1953, Churchill suggested that the United States allow Britain to have access to American nuclear weapons to make up the shortfall. The provision on American weapons was called
Project E Project E was a joint project between the United States and the United Kingdom during the Cold War to provide nuclear weapons to the Royal Air Force (RAF) until sufficient British nuclear weapons became available. It was subsequently expanded ...
. The agreement was confirmed by Eisenhower and Macmillan, who was now the Prime Minister, during their March 1957 meeting in Bermuda, and a formal Memorandum of Understanding (MOU) was signed on 21 May 1957. Four squadrons of
English Electric Canberra The English Electric Canberra is a British first-generation, jet-powered medium bomber. It was developed by English Electric during the mid- to late 1940s in response to a 1944 Air Ministry requirement for a successor to the wartime de Havil ...
bombers based in Germany were equipped with US
Mark 7 nuclear bomb Mark 7 " Thor" (or Mk-7') was the first tactical fission bomb adopted by US armed forces. It was also the first weapon to be delivered using the toss method with the help of the low-altitude bombing system (LABS). The weapon was tested in Operati ...
s stored at
RAF Germany The former Royal Air Force Germany (RAFG) was a command of the Royal Air Force and part of British Forces Germany. It consisted of units located in Germany, initially as part of the occupation following the Second World War, and later as part o ...
bases. There were also four squadrons of nuclear-armed Canberras based in the UK, which were capable of carrying either the Mark 7 or Red Beard. They too were assigned to the SACEUR in October 1960. The planned V-bomber force was reduced to 144 aircraft, and it was intended to equip half of them with Project E weapons, so 72
Mark 5 nuclear bomb The Mark 5 nuclear bomb and W5 nuclear warhead were a common core American nuclear weapon design, designed in the early 1950s and which saw service from 1952 to 1963. Description The Mark 5 design was the first production American nuclear weapon ...
s were supplied for the V-bombers. When the MDA came into force, the US agreed to supply the V-bombers with megaton weapons in place of the Mark 5, in the form of
Mark 15 Mark 15 is the fifteenth chapter of the Gospel of Mark in the New Testament of the Christian Bible. This chapter records the narrative of Jesus' passion, including his trial before Pontius Pilate and then his crucifixion, death and entombmen ...
and Mark 39 nuclear bombs. Under the Project E MOU, US personnel had custody of the weapons. This meant they performed all the tasks related to their storage, maintenance and readiness. The bombs were stored in Secure Storage Areas (SSAs) on the same bases as the bombers which British staff were not permitted to enter. It was therefore impossible to store British and American bombs together in the same SSA. US custody also created operational problems. The procedure for handing over the bombs added an extra ten minutes to the bombers' reaction time, and the requirement that US personnel had guardianship of the weapons at all times meant that neither they nor the bombers could be relocated to dispersal airfields as the RAF desired. The operational restrictions imposed by Project E "effectively handed the US government a veto over the use of half of Britain's nuclear deterrent". The Air Council decided on 7 July 1960 that Project E weapons would be phased out by December 1962, by which time it was anticipated that there would be sufficient British megaton weapons to equip the entire
strategic bomber A strategic bomber is a medium- to long-range Penetrator (aircraft), penetration bomber aircraft designed to drop large amounts of air-to-ground weaponry onto a distant target for the purposes of debilitating the enemy's capacity to wage war. Unl ...
force. Project E weapons were replaced by British Yellow Sun bombs. Problems encountered in the development of Red Beard meant that the replacement of kiloton weapons took longer than anticipated. The Air Ministry decided to replace the Canberras with Valiants as the long-range Vulcan and Victor V bombers became available. A Valiant squadron at
RAF Marham RAF Marham is a Royal Air Force station and military airbase near the village of Marham in the English county of Norfolk, East Anglia. It is home to No. 138 Expeditionary Air Wing (138 EAW) and, as such, is one of the RAF's "Main Operating Ba ...
was assigned to SACEUR on 1 January 1961, followed by two more in July. The UK-based Canberra squadrons were then disbanded. Each of the 24 Valiants was equipped with two Project E Mark 28 nuclear bombs. These were replaced by the newer Mark 43 nuclear bombs in early 1963. The Valiants were withdrawn from service in 1965. Project E nuclear warheads were also used on the sixty
Thor Thor (; from non, Þórr ) is a prominent god in Germanic paganism. In Norse mythology, he is a hammer-wielding god associated with lightning, thunder, storms, sacred groves and trees, strength, the protection of humankind, hallowing, ...
Intermediate Range Ballistic Missiles (IRBMs) that were operated by the RAF from 1959 to 1963 under Project Emily. During the
Cuban Missile Crisis The Cuban Missile Crisis, also known as the October Crisis (of 1962) ( es, Crisis de Octubre) in Cuba, the Caribbean Crisis () in Russia, or the Missile Scare, was a 35-day (16 October – 20 November 1962) confrontation between the United S ...
, the RAF's bombers and Thor missiles targeted 16 cities, 44 airfields, 10 air defence control centres and 20 IRBM sites. The RAF high command never warmed to missiles, and always ranked them secondary to the V bomber force. The missile bases were separate from the rest of the RAF and its personnel considered outside the mainstream. Project Emily gave the RAF considerable experience in missile operations, but the 1960 cancellation of Blue Streak in favour of the American
Skybolt The Douglas GAM-87 Skybolt (AGM-48 under the 1962 Tri-service system) was an air-launched ballistic missile (ALBM) developed by the United States during the late 1950s. The basic concept was to allow US strategic bombers to launch their weapons ...
, an
air-launched ballistic missile An air-launched ballistic missile or ALBM is a ballistic missile launched from an aircraft. An ALBM allows the launch aircraft to stand off at long distances from its target, keeping it well outside the range of defensive weapons like anti-aircr ...
, rendered this expertise of dubious value. An Air Council meeting on 31 May 1962 decided that Project Emily should be terminated by the end of 1963, and the last Thor squadrons were inactivated on 23 August 1963. The British Army purchased 113 Corporal missiles from the United States in 1954. It was intended that they would be equipped with British warheads under a project codenamed Violet Vision, but Project E offered a quicker, simpler and cheaper alternative. The US supplied 100 W7 warheads, which had to be drawn from US Army storage sites in southern Germany until arrangements were made for local storage in August 1959. A British missile, Blue Water, with an Indigo Hammer warhead, was developed to replace Corporal. The US offered the
Honest John missile The MGR-1 Honest John rocket was the first nuclear-capable surface-to-surface rocket in the United States arsenal.The first nuclear-authorized ''guided'' missile was the MGM-5 Corporal. Originally designated Artillery Rocket XM31, the first uni ...
as an interim replacement. The offer was accepted, and 120 Honest John missiles with W31 warheads were supplied in 1960, enough to equip three artillery regiments. Blue Water was cancelled in July 1962, and Honest John remained in service until 1977, when it was replaced by the Lance missile. The US also supplied the
British Army of the Rhine There have been two formations named British Army of the Rhine (BAOR). Both were originally occupation forces in Germany, one after the First World War and the other after the Second World War. Both formations had areas of responsibility located ...
(BAOR) with 36 W33 nuclear warheads that equipped four batteries of eight-inch M115 howitzers. These were later replaced by M110 howitzers. The British Army deployed more US nuclear weapons than the RAF and Royal Navy combined, peaking at 327 out of 392 in 1976–1978. A maritime version of Project E, known as Project N supplied US Navy weapons. Providing American atomic bombs for Royal Navy ships would have involved similar dual key arrangements and detachments of
US Marines The United States Marine Corps (USMC), also referred to as the United States Marines, is the maritime land force service branch of the United States Armed Forces responsible for conducting expeditionary and amphibious operations through comb ...
on board Royal Navy ships, which was deemed impractical even for ships and weapons dedicated to use in European waters. However, RAF
Coastal Command RAF Coastal Command was a formation within the Royal Air Force (RAF). It was founded in 1936, when the RAF was restructured into Fighter, Bomber and Coastal Commands and played an important role during the Second World War. Maritime Aviation ...
acquired Mk 101 Lulu
nuclear depth bomb A nuclear depth bomb is the nuclear equivalent of the conventional depth charge, and can be used in anti-submarine warfare for attacking submerged submarines. The Royal Navy, Soviet Navy, and United States Navy had nuclear depth bombs in their ...
s (with the W34 nuclear warhead) for its
Avro Shackleton The Avro Shackleton is a British long-range maritime patrol aircraft (MPA) which was used by the Royal Air Force (RAF) and the South African Air Force (SAAF). It was developed by Avro from the Avro Lincoln bomber, which itself had been a develo ...
and Hawker Siddeley Nimrod maritime patrol aircraft from 1965 to 1971 under Project N. These were later replaced by the more capable Mark 57, which was stockpiled at
RAF St Mawgan Royal Air Force St Mawgan or more simply RAF St Mawgan is a Royal Air Force station near St Mawgan and Newquay in Cornwall, England. In 2008 the runway part of the site was handed over to Newquay Airport. The remainder of the station continues t ...
and RAF Machrihanish. When the Cold War ended in 1991, the BAOR still had about 85 Lance missiles, and more than 70 W33 eight-inch and
W48 The W48 was an American nuclear artillery shell, capable of being fired from any standard howitzer. A tactical nuclear weapon, it was manufactured starting in 1963, and all units were retired in 1992. It was known as the XM454 AFAP (artillery ...
155 mm nuclear artillery shells. The last Project E warheads, including the Mark 57 nuclear depth bombs and those used by the BAOR, were withdrawn in July 1992.


US nuclear weapons in US service in the UK

In the early years of the Cold War, the majority of the bomber force of the US
Strategic Air Command Strategic Air Command (SAC) was both a United States Department of Defense Specified Command and a United States Air Force (USAF) Major Command responsible for command and control of the strategic bomber and intercontinental ballistic missile ...
(SAC) was made up of World War II vintage
Boeing B-29 Superfortress The Boeing B-29 Superfortress is an American four-engined propeller-driven heavy bomber, designed by Boeing and flown primarily by the United States during World War II and the Korean War. Named in allusion to its predecessor, the B-17 Fl ...
bombers, and their successors, the
Boeing B-50 Superfortress The Boeing B-50 Superfortress is an American strategic bomber. A post– World War II revision of the Boeing B-29 Superfortress, it was fitted with more powerful Pratt & Whitney R-4360 radial engines, stronger structure, a taller tail fin, and ...
and the
Boeing B-47 Stratojet The Boeing B-47 Stratojet (Boeing company designation Model 450) is a retired American long- range, six-engined, turbojet-powered strategic bomber designed to fly at high subsonic speed and at high altitude to avoid enemy interceptor aircraft ...
, all of which lacked the range to reach targets in the Soviet Union from bases in the continental United States. Only the small number of
Convair B-36 Peacemaker The Convair B-36 "Peacemaker" is a strategic bomber that was built by Convair and operated by the United States Air Force (USAF) from 1949 to 1959. The B-36 is the largest mass-produced piston-engined aircraft ever built. It had the longest w ...
bombers could do this. Overseas bases were therefore required, and the need for bases in the UK was a feature of American war planning for over a decade. Obtaining British permission was easy thanks to the wartime comradeship between the RAF and the United States Army Air Forces (USAAF). Bypassing the politicians,
General A general officer is an officer of high rank in the armies, and in some nations' air forces, space forces, and marines or naval infantry. In some usages the term "general officer" refers to a rank above colonel."general, adj. and n.". O ...
Carl Spaatz Carl Andrew Spaatz (born Spatz; June 28, 1891 – July 14, 1974), nicknamed "Tooey", was an American World War II general. As commander of Strategic Air Forces in Europe in 1944, he successfully pressed for the bombing of the enemy's oil produc ...
, the commander of the USAAF, came to an agreement with the Chief of the Air Staff, Marshal of the Royal Air Force Lord Tedder, in June and July 1946. Work began on extended and strengthened runways at RAF airbases in East Anglia to receive the B-29s. In June 1947, nine B-29s of the 97th Bombardment Group deployed to RAF Marham, where they were greeted by Tedder. This was merely a test; the bombers were not nuclear-capable. Only the Silverplate B-29s of the
509th Bombardment Group 5 (five) is a number, numeral and digit. It is the natural number, and cardinal number, following 4 and preceding 6, and is a prime number. It has attained significance throughout history in part because typical humans have five digits on eac ...
could do so. Their first deployment was in April 1949. Ninety sets of bomb assemblies—atomic bombs without the fissile cores—were stored in the UK by July 1950, and authority to deploy the cores as well was given in April 1954. The
3rd Air Division The 3rd Air Division (3d AD) is an inactive United States Air Force organization. Its last assignment was with Strategic Air Command, assigned to Fifteenth Air Force, being stationed at Hickam AFB, Hawaii. It was inactivated on 1 April 1992. ...
was formed in 1949 to control the deployments of B-29s to the UK. It was soon upgraded to the status of a major command, and became the
Third Air Force The Third Air Force (Air Forces Europe) (3 AF) is a numbered air force of the United States Air Forces in Europe - Air Forces Africa (USAFE-AFAFRICA). Its headquarters is Ramstein Air Base, Germany. It is responsible for all U.S. air forces in ...
in May 1951 as part of the
United States Air Forces in Europe United may refer to: Places * United, Pennsylvania, an unincorporated community * United, West Virginia, an unincorporated community Arts and entertainment Films * ''United'' (2003 film), a Norwegian film * ''United'' (2011 film), a BBC Two f ...
. SAC then formed the
7th Air Division The 7th Air Division (7 AD) served the United States Air Force with distinction from early 1944 through early 1992, earning an outstanding unit decoration and a service streamer along the way. History Hawaii As the 7th Fighter Wing, the divis ...
to control the nuclear bomber deployments. With the introduction to service of long-range bombers and
intercontinental ballistic missile An intercontinental ballistic missile (ICBM) is a ballistic missile with a range greater than , primarily designed for nuclear weapons delivery (delivering one or more thermonuclear warheads). Conventional, chemical, and biological weapo ...
s, the need for a SAC presence in the UK diminished, On 3 April 1964, the last SAC aircraft, a B-47 from the 380th Bombardment Wing, left RAF Brize Norton, ending nearly 12 years' of continual B-47 deployments, and the 7th Air Division on 30 June 1964. During the later Cold War years,
Boeing B-52 Stratofortress The Boeing B-52 Stratofortress is an American long-range, subsonic, jet-powered strategic bomber. The B-52 was designed and built by Boeing, which has continued to provide support and upgrades. It has been operated by the United States Air ...
bombers became regular visitors to the United Kingdom, turning up at bases such as RAF Greenham Common and also taking part in RAF Bomber competitions, but were deployed to NATO on an individual basis, not as groups or wings. In 1962 there were one or two visits each month. In fulfilment of NATO's plans to halt a Soviet invasion of Western Europe using tactical nuclear weapons, the 3rd Air Force received its own nuclear weapons when the 20th Fighter Wing deployed to RAF Wethersfield in Essex on 1 June 1952, with Republic F-84F Thunderstreak fighters and Mark 7 nuclear bombs. It reequipped with the
North American F-100 Super Sabre The North American F-100 Super Sabre is an American supersonic jet fighter aircraft that served with the United States Air Force (USAF) from 1954 to 1971 and with the Air National Guard (ANG) until 1979. The first of the Century Series of ...
in 1957, and the General Dynamics F-111 in 1970. In the 1970s, up to 60 F-111s based in the UK were on quick reaction alert, each carrying multiple
B61 nuclear bomb The B61 nuclear bomb is the primary thermonuclear gravity bomb in the United States Enduring Stockpile following the end of the Cold War. It is a low to intermediate-yield strategic and tactical nuclear weapon featuring a two-stage radiation im ...
s. US Navy Polaris ballistic missile submarines were based at Holy Loch in Scotland from March 1961. During the 1980s nuclear armed USAF
Ground Launched Cruise Missile The Ground Launched Cruise Missile, or GLCM, (officially designated BGM-109G Gryphon) was a ground-launched cruise missile developed by the United States Air Force in the last decade of the Cold War and disarmed under the INF Treaty. Overview T ...
s (GLCMs) were deployed at RAF Greenham Common and
RAF Molesworth Royal Air Force Molesworth or more simply RAF Molesworth is a Royal Air Force station located near Molesworth, Cambridgeshire, England with a history dating back to 1917. Its runway and flight line facilities were closed in 1973 and demolished ...
, as a consequence of the 1979 NATO Double-Track Decision, under which NATO countries agreed to modernise the alliance's nuclear weapons. Under the terms of the 1987
Intermediate-Range Nuclear Forces Treaty The Intermediate-Range Nuclear Forces Treaty (INF Treaty, formally the Treaty Between the United States of America and the Union of Soviet Socialist Republics on the Elimination of Their Intermediate-Range and Shorter-Range Missiles; / ДРСМ� ...
with the Soviet Union, the United States withdrew its surface naval nuclear weapons and short-range nuclear forces. The GLCMs were withdrawn from the UK in 1991, and the Polaris submarine base at Holy Loch was closed in 1992. The US continued to store tactical nuclear weapons in the UK until 2006, when approximately 110 tactical B61s stored at
RAF Lakenheath Royal Air Force Lakenheath or RAF Lakenheath is a Royal Air Force station near the village of Lakenheath in Suffolk, England, UK, north-east of Mildenhall and west of Thetford. The base also sits close to Brandon. Despite being an RAF sta ...
for deployment by USAF
F-15E Strike Eagle The McDonnell Douglas (now Boeing) F-15E Strike Eagle is an American all-weather multirole strike fighter derived from the McDonnell Douglas F-15 Eagle. The F-15E was designed in the 1980s for long-range, high-speed interdiction without rely ...
aircraft were removed.


British nuclear weapons

The MDA made fully developed and tested American designs available quickly and cheaply. The first of these was the Mark 28, which was "Anglicised" and manufactured in the UK as Red Snow. Exact copies of American designs were not pursued; the high explosive used in American warheads were more sensitive than British high explosive, and had caused fatal accidents in the US. Its use was not contemplated in the UK after an accident at Aldermaston on 28 February 1959 when two men were killed after a piece of British high explosive fell from a lorry. British high explosive was also bulkier, so a redesign was required. Red Snow was far more economical in its use of fissile material than the Green Grass warhead in the Yellow Sun Mk.1 bomb, Britain's first production hydrogen bomb. A Yellow Sun Mk.2 with Red Snow, therefore, cost £500,000 compared to £1.2 million for the Mk.1. RAF Bomber Command wanted Violet Club replaced as soon as possible, so 37 Yellow Sun Mk.1s were delivered by the end of 1959. Deliveries of the Yellow Sun Mk.2 commenced in January 1961, and 43 were delivered by the end of the year. In November 1958. Red Snow also replaced Green Grass as the warhead in the Blue Steel stand-off missile. The kiloton Red Beard was developed for use by the Canberras and the Royal Navy's
Fleet Air Arm The Fleet Air Arm (FAA) is one of the five fighting arms of the Royal Navy and is responsible for the delivery of naval air power both from land and at sea. The Fleet Air Arm operates the F-35 Lightning II for maritime strike, the AW159 Wi ...
. Technical problems delayed its introduction into service, but over 100 were delivered by the end of 1961. Up to 48 Red Beards were secretly stowed in a highly secured weapons storage facility at
RAF Tengah ''Tengah'' is an Indonesian and Malay word meaning "Central". It can be found in topography, e.g. *Kalimantan Tengah *Tengah Islands or Central Archipelago. *Tengah, Singapore *Tengah Air Base The Tengah Air Base is a military airbase of t ...
in Singapore between 1962 and 1971 for possible use by V bombers and for Britain's military commitment to SEATO. The availability of US weapons and designs under the MDA led to the cancellation of several research projects.
Indigo Hammer Indigo is a deep color close to the color wheel blue (a primary color in the RGB color space), as well as to some variants of ultramarine, based on the ancient dye of the same name. The word "indigo" comes from the Latin word ''indicum'', m ...
and the smaller Pixie were warheads intended for use with the Red Duster and Seaslug
surface-to-air missile A surface-to-air missile (SAM), also known as a ground-to-air missile (GTAM) or surface-to-air guided weapon (SAGW), is a missile designed to be launched from the ground to destroy aircraft or other missiles. It is one type of anti-aircraft syst ...
s; a British version of the US W44 was chosen instead.
Blue Peacock Blue Peacock, renamed from Blue Bunny and originally Brown Bunny, was a British tactical nuclear weapon project in the 1950s. The project's goal was to store a number of ten-kiloton nuclear land mines in Germany. These mines which were intende ...
, a atomic demolition munition (ADMs) based on Blue Danube, was cancelled in 1958 in favour of the lighter Violet Mist, based on Red Beard. The development of the even smaller and lighter US ADMs led to its cancellation as well in 1961. The US
Medium Atomic Demolition Munition Medium Atomic Demolition Munition (MADM) was a tactical nuclear weapon developed by the United States during the Cold War. It was an Atomic demolition munition, a combat engineering device for demolition of structures and for battlefield shaping ...
with the
W45 The W45 was a multipurpose American nuclear warhead developed in the early 1960s, first built in 1962 and fielded in some applications until 1988. It had a diameter of 11.5 inches (292 mm), a length of 27 inches (686 mm) and weighed 150 pounds ( ...
was acquired instead. Yellow Anvil was a British artillery warhead that was cancelled in 1958. In 1960, the government decided to cancel the
Blue Streak missile The de Havilland Propellers Blue Streak was a British Intermediate-range ballistic missile (IRBM), and later the first stage of the Europa satellite launch vehicle. Blue Streak was cancelled without entering full production. The project was ...
based on the Chiefs of Staff's conclusion that it was too vulnerable to attack and thus was only useful for a first strike, and decided to purchase the American air-launched Skybolt missile instead. Macmillan met with Eisenhower in March 1960, and secured permission to buy Skybolt without strings attached. In return, the Americans were given permission to base the US Navy's
Polaris Polaris is a star in the northern circumpolar constellation of Ursa Minor. It is designated α Ursae Minoris ( Latinized to ''Alpha Ursae Minoris'') and is commonly called the North Star or Pole Star. With an apparent magnitude th ...
-equipped
ballistic missile submarine A ballistic missile submarine is a submarine capable of deploying submarine-launched ballistic missiles (SLBMs) with nuclear warheads. The United States Navy's hull classification symbols for ballistic missile submarines are SSB and SSBN � ...
s at
Holy Loch The Holy Loch ( gd, An Loch Sianta/Seunta) is a sea loch, a part of the Cowal peninsula coast of the Firth of Clyde, in Argyll and Bute, Scotland. The "Holy Loch" name is believed to date from the 6th century, when Saint Munn landed there a ...
in Scotland. The Americans initially intended to pair Skybolt with the W47 warhead, an innovative light-weight design from the Lawrence Radiation Laboratory developed for Polaris. The British wanted to use Red Snow, partly for safety reasons and partly because it was not certain that the advanced M47 design would be made available without strings attached. The technical problem was that Red Snow was heavier, and therefore the range of the Skybolt would be reduced from . A megaton design known as RE.179 based on the
W49 The W49 was an American thermonuclear warhead, used on the Thor, Atlas, Jupiter, and Titan I ballistic missile systems. W49 warheads were manufactured starting in 1958 and were in service until 1965, with a few warheads being retained until 197 ...
warhead used in American ICBMs was developed for Skybolt. At the same time, work was in progress on a Red Beard replacement for use with the RAF's
BAC TSR-2 The British Aircraft Corporation TSR-2 is a cancelled Cold War strike and reconnaissance aircraft developed by the British Aircraft Corporation (BAC), for the Royal Air Force (RAF) in the late 1950s and early 1960s. The TSR-2 was designed ...
and the Royal Navy's Blackburn Buccaneer. Ultimately, a warhead was produced in two variants: the high-yield () WE.177B and the low-yield () WE.177A as a Red Beard replacement, and for use in depth charges and anti-submarine missiles. WE.177 was later adapted for use with Polaris, and would become the longest-serving British nuclear weapon. The deployment of ships carrying nuclear weapons caused complications during the Falklands War, and in the aftermath of that war it was decided to stockpile them ashore in peacetime. When the US withdrew its theatre nuclear weapons from Europe, the British government followed suit. The nuclear depth bombs were withdrawn from service in 1992, followed by the WE.177 free-fall bombs on 31 March 1998, and all were dismantled by the end of August.


Research and production facilities

The Atomic Weapons Establishment (AWE), Aldermaston, formerly the Atomic Weapons Research Establishment (AWRE), is situated on a site near Reading, Berkshire, Reading in Berkshire. It was built on the site of the former RAF Aldermaston, which was converted to nuclear weapons research, design and development establishment, and opened on 1 April 1950. In 1954, the AWRE took control of the nearby ROF Burghfield, where warheads were assembled, and the test ranges at Foulness and Orford Ness. Components for nuclear weapons were also produced at the former ROF Cardiff site. The Atomic Weapons Research Establishment became part of the United Kingdom Atomic Energy Authority on 1 January 1955. The last trials at Orford Ness were conducted on 9 June 1971, and the site was closed on 1 October 1971. Cardiff closed in 1997, and Foulness by the end of that year. In 1989, the government announced its intention to find a private company to run AWE, with the government retaining ownership of the site and control of AWE though a golden share arrangement. In 1993, the contract was awarded to a consortium of Hunting Engineering, Brown and Root and AEA Technology. In 1999, the contract was transferred to a consortium of BNFL, Lockheed Martin and Serco. In 2008, the British government sold the BNFL share to Jacobs Engineering Group.


Polaris

The Kennedy administration cancelled Skybolt in December 1962 because the United States Secretary of Defense, Robert McNamara, determined that other delivery systems were progressing better than expected, and a further expensive system was surplus to US requirements. In London, over one hundred Conservative members of Parliament, nearly one third of the parliamentary party, signed a motion urging Macmillan to ensure that Britain remained an independent nuclear power. Macmillan met with President John F. Kennedy and brokered the Nassau Agreement. Macmillan rejected offers of other systems, and insisted that the UK needed to purchase Polaris submarine-launched ballistic missiles. These represented more advanced technology than Skybolt, and the US was not inclined to provide them except as part of a Multilateral Force within the North Atlantic Treaty Organization (NATO). In the end, Kennedy did not wish to see Macmillan's government collapse, which would imperil Britain's entry into the European Economic Community (EEC), so a face-saving compromise was reached: the US agreed to provide the UK with Polaris missiles, which would be assigned to NATO, and could be used independently only when "supreme national interests" intervened. The
Polaris Sales Agreement The Polaris Sales Agreement was a treaty between the United States and the United Kingdom which began the UK Polaris programme. The agreement was signed on 6 April 1963. It formally arranged the terms and conditions under which the Polaris mi ...
was signed on 6 April 1963. The UK retained its deterrent force, although its control passed from the RAF to the Royal Navy. The Polaris missiles were equipped with British warheads. A base was developed for the Polaris submarines at Faslane on the Firth of Clyde, not far from the US Navy's base at Holy Loch. It was served by a weapons store at nearby RNAD Coulport, Coulport. The first of four Polaris submarines, was launched in September 1966, and commenced its first deterrent patrol in June 1968. The annual running costs of the Polaris boats came to around two per cent of the defence budget, and they came to be seen as a credible deterrent that enhanced Britain's international status. British politicians did not like to talk about "dependence" on the United States, preferring to describe the Special Relationship as one of "interdependence". Polaris had not been designed to penetrate anti-ballistic missile (ABM) defences, but the Royal Navy had to ensure that its small Polaris force operating alone, and often with only one submarine on patrol, could penetrate the ABM screen around Moscow. The Second Wilson ministry (United Kingdom), Wilson government publicly ruled out the purchase of Poseidon missiles in June 1967, and without such a commitment, the Americans were unwilling to share information about warhead vulnerability. The result was Chevaline, an Improved Front End (IFE) that replaced one of the three warheads with multiple decoys and other defensive countermeasures, in what was known as a Penetration Aid Carrier (PAC). It was the most technically complex defence project ever undertaken in the United Kingdom. Chevaline's existence, along with its formerly secret codename, was revealed by the Secretary of State for Defence, Francis Pym, during a debate in the House of Commons on 24 January 1980. By this time the project had gone on for a decade. The final cost reached £1,025 million.


Trident

In 1982, the First Thatcher ministry, Thatcher government announced its decision to purchase 65 American UGM-133 Trident II, Trident II D-5 missiles. These operated as part of a shared pool of weapons based at Naval Submarine Base Kings Bay in the United States. The US would maintain and support the missiles, while the UK would manufacture its own submarines and warheads. The warheads and missiles would be mated in the UK. Four s were designed and built. Trident missiles had
multiple independently targetable re-entry vehicle A multiple independently targetable reentry vehicle (MIRV) is an exoatmospheric ballistic missile payload containing several warheads, each capable of being aimed to hit a different target. The concept is almost invariably associated with int ...
(MIRV) capability, which was needed to overcome the Soviet ABM defences. Each submarine could carry up to 16 missiles, each of which can each carry up to 8 warheads. However, when the decision to purchase Trident II was announced, it was stressed that British Trident boats would carry no more than 128 warheads—the same number as Polaris. In November 1993, the Secretary of State for Defence, Malcolm Rifkind, announced that each boat would deploy no more than 96 warheads. In 2010, this was reduced to a maximum of 40 warheads, split between eight missiles. The missiles have a range of . The first Trident boat, , collected a full load of 16 missiles in 1994, but the second, drew only 12 in 1995, and the third, , 14 in 1997, leaving the remaining missile tubes empty. Although the UK designed, manufactured and owns the warheads, there is evidence that the warhead design is similar to, or even based on, the US W76 warhead fitted in some US Navy Trident missiles, with design data being supplied by the United States through the MDA. Since 1969, the United Kingdom has always had at least one ballistic-missile submarine on patrol, giving it a nuclear deterrent that is, what the Defence Council of the United Kingdom, Defence Council described in 1980 as, "effectively invulnerable to pre-emptive attack". In the Strategic Defence Review published in July 1998, the government stated that once the ''Vanguard'' submarines became fully operational (the fourth and final one, , entered service on 27 November 1999), it would "maintain a stockpile of fewer than 200 operationally available warheads". , the UK had a stockpile of 215 warheads, of which 120 were operational. The 2010 Strategic Defence and Security Review reduced the number of warheads and missiles for the ballistic missile submarine on patrol to 40 and 8 respectively. Nuclear warheads from the Trident missiles are transported by road convoy several times a year from Coulport to Burghfield for refurbishment. Between 2000 and 2016, there were 180 accidents involving the vehicles, ranging from minor traffic accidents to a sudden total loss of power in one of the 44-tonne lorries that halted a convoy and caused a double lane closure and a traffic congestion, tailback on the M6 motorway. The accidents have been more frequent in recent years. The Trident system cost £12.6 billion to build (at 1996 prices) and £280m a year to maintain. Options for replacing Trident ranged from £5 billion for the missiles alone to £20 to £30 billion for missiles, submarines and research facilities. At a minimum, for the system to continue after around 2020, the missiles would need to be replaced. By 2016, the price of replacement of submarine had risen to £31 billion and it was estimated by Ministry of Defence that the cost of Trident replacement programme for 30 years would be £167 billion.


Trident renewal

With the tactical nuclear weapons having been withdrawn from service, Trident was the UK's only remaining nuclear weapons system. By this time, possession of nuclear weapons had become an important part of Britain's national identity. Not renewing Trident meant that Britain would become a non-nuclear power and strike at Britain's status as a great power. A decision on the renewal of Trident was made on 4 December 2006. Prime Minister Tony Blair told MPs it would be "unwise and dangerous" for the UK to give up its nuclear weapons. He outlined plans to spend up to £20bn on a new generation of ballistic missile submarines. The new boats would continue to carry the Trident II D-5 missiles, but submarine numbers might be cut from four to three, and the number of nuclear warheads would reduced by 20% to 160. He said although the Cold War had ended, the UK needed nuclear weapons, as no-one could be sure another nuclear threat would not emerge in the future. The 2010 United Kingdom government formation, 2010 coalition government agreed "that the renewal of Trident should be scrutinised to ensure value for money. Liberal Democrats will continue to make the case for alternatives." Research and development work continued, but the final decision to proceed with building a replacement was scheduled for 2016, after the next election. There was already some urgency to move ahead because some experts predicted it could take 17 years to develop the replacement for the ''Vanguard''-class submarines. The vote in the House of Commons of the United Kingdom, House of Commons on whether to replace the existing four ''Vanguard''-class submarines was held on 18 July 2016. The Trident renewal programme motion passed with a significant majority with 472 MPs voting in favour and 117 against. The Leader of the Opposition (United Kingdom), Leader of the Opposition, Jeremy Corbyn, and 47 other Labour MPs had voted against it; 41 did not vote but 140 Labour votes were cast in favour of the motion. The Successor class was officially named the on 21 October 2016. The four new ''Dreadnought'' submarines were expected to come into operation in the early 2030s, with the programme lasting until at least the 2060s. The government released a written statement on 25 February 2020, outlining that the UK nuclear warheads will be replaced and will match the US Trident II SLBM and related systems. The commander of the US Strategic Command, Admiral Charles A. Richard, told a US Senate hearing that the UK was already working to replace its warheads. The new UK warhead was planned to fit inside the future US Mk7 aeroshell that would house the future US W93 warhead. It would be the first UK-designed warhead in thirty years, since the Holbrook, an Anglicised version of the US W76. However, the US Congress was reluctant to authorise the US$32 million in funding for the first phase of design of the new aeroshell. Meanwhile, construction of the £634 million Pegasus enriched uranium facility was suspended in 2018, the £1,806 million Mensa warhead assembly facility was still under construction, and the proposed Hydrus facility for hydrodynamic weapons testing was cancelled in favour of using the French Teutates-Epur facility in Valduc.


Nuclear tests

The UK's first nuclear test, Operation Hurricane, was in the Montebello Islands of Western Australia. It was followed by the first nuclear tests on the Australian mainland, which were conducted at Emu Field in the Great Victoria Desert in South Australia as part of Operation Totem on 14 and 26 October 1953. Two further tests were held on the Montebello Islands as part of Operation Mosaic on 6 May and 19 June 1956. In the 1980s there emerged a claim that the second Mosaic test was of a significantly higher explosive yield than suggested by available figures— as compared to the official figure of —but this claim does not stand up to scrutiny. The British government formally requested a permanent test facility on 30 October 1953. Due to concerns about nuclear fallout from the previous tests at Emu Field and the site's inadequate infrastructure and water supply, the recently surveyed site at Maralinga, South Australia, Maralinga in South Australia was selected for this purpose.Atomic Weapons Tests in: The new site was announced in May 1955.Sources give slightly varying dates for the request and selection of the site. It was developed as a joint, co-funded facility between the British and Australian governments. Seven British nuclear tests at Maralinga were conducted between 27 September 1956 and 9 October 1957. In addition to the major tests involving explosions, many subcritical testing, subcritical minor trials were also carried out between June 1955 and April 1963. While the major tests had been carried out with some publicity, the minor tests were carried out in absolute secrecy. The "Kitten" tests tested bomb components, while "Tims" and "Rats" were early subcritical hydronuclear tests. The "Vixen" tests involved safety testing of nuclear weapons—assuring that the core would not accidentally undergo criticality in the event of a fire or crash. These minor tests left a legacy of radioactive contamination at Maralinga. The Australian government prohibited hydrogen bomb tests in Australia, so Britain had to look for another test site for its hydrogen bombs. The first British hydrogen bombs were tested during Operation Grapple at Malden Island and Kiritimati, Christmas Island in the Pacific Ocean. Nine tests were conducted there in 1957, 1958 and 1959, ultimately demonstrating that the UK had developed expertise in thermonuclear weapons. Beginning in December 1962, the UK conducted 24 tests at the Nevada Test Site in the United States. The final test was the Julin Bristol shot which took place on 26 November 1991. British nuclear testing was abruptly halted by President George H. W. Bush in October 1992. Because Britain did not test as often as the United States for financial and political reasons, and did not have the Americans' state-of-the-art computer facilities, British weapons design depended more on theoretical understanding, with potential for both greater advances and greater risks between tests. The United Kingdom, along with the United States and the Soviet Union, signed the Partial Test Ban Treaty, which restricted it to underground nuclear tests by outlawing testing in the atmosphere, underwater, or in outer space, on 5 August 1963. The UK signed the Comprehensive Test Ban Treaty, ending all nuclear testing, on 24 September 1996, and ratified it on 6 April 1998, having passed the necessary legislation on 18 March 1998 as the Nuclear Explosions (Prohibition and Inspections) Act 1998. Subcritical nuclear tests continued to occur, most notably the Etna test in February 2002, and the Krakatau test in February 2006. Altogether forty-five nuclear tests were carried out by the United Kingdom between 3 October 1952 to 26 November 1991 at the Montebello Islands, Emu Field and Maralinga in Australia, on Christmas and Malden Islands in Kiribati, and at the Nevada Test Site in the United States. The 45 tests included 21 tests carried out in the atmosphere.


Nuclear defence

Britain was extremely vulnerable to nuclear weapons. The 1955 Strath Committee grimly estimated that an attack on the UK with just ten 10-megaton weapons would kill 12 million people and seriously injure another 4 million even before the country was blanketed with radioactive fallout.


Warning systems

The UK has relied on the Ballistic Missile Early Warning System (BMEWS) and, in later years, Defense Support Program (DSP) satellites for warning of a nuclear attack. Both of these systems are owned and controlled by the United States, although the UK has joint control over UK-based systems. One of the four component radars for the BMEWS is based at RAF Fylingdales in North Yorkshire. In 2003, the UK government stated that it would consent to a request from the US to upgrade the radar at Fylingdales for use in the US National Missile Defense system, but missile defence was not a significant political issue within the UK. The ballistic missile threat was perceived to be less severe, and consequently less of a priority, than other threats to its security. Fylingdales was enhanced to an Upgraded Early Warning Radar (UEWR) in 2008, and became part of the United States national missile defense system in 2011.


Attack scenarios

During the Cold War, a significant effort by government and academia was made to assess the effects of a nuclear attack on the UK. There were four major exercises: * Exercise Inside Right took place in 1975. * Exercise Scrum Half was conducted in 1978. * Exercise Square Leg was conducted in 1980. The scenario involved around 130 warheads with a total yield of 205 megatons (69 ground burst, 62 air burst) with an average of 1.5 megatons per bomb. The exercise was criticised as unrealistic as an actual exchange may be much larger or smaller, and did not include targets in Inner London such as Whitehall. Even so, the effect of the limited attack in Square Leg was estimated to be 29 million dead (53 per cent of the population) and 6.4 million seriously injured. * Exercise Hard Rock was a combined communications and civil defence exercise planned for September and October 1982. It assumed a conventional war in Europe lasting two to three days, during which the UK would be attacked with conventional weapons, then a limited nuclear exchange, with 54 nuclear warheads used against military targets in the UK. 250,000 people protested against the exercise and 24 councils refused to participate. The limited scenario still assumed casualties of 7.9 million dead and 5 million injured. The scenario was ridiculed by the Campaign for Nuclear Disarmament and the exercise was postponed indefinitely. The ''New Statesman'' later claimed the Ministry of Defence insisted on having a veto over proposed targets in the exercise and several were removed to make them politically more acceptable; for example, the nuclear submarine base at Faslane was removed from the target list.


Civil defence

Successive governments developed civil defence programmes aimed to prepare civilian and local government infrastructure for a nuclear strike on the UK. A series of seven Civil Defence Bulletin films were produced in 1964, and in the 1980s the most famous such programme was probably the series of booklets and public information films entitled ''Protect and Survive''. The booklet contained information on building a Fallout shelter, nuclear refuge within a so-called "fall-out room" at home, sanitation, limiting fire hazards, and descriptions of the audio signals for attack warning, fall-out warning and all clear. It was anticipated that families might need to stay in their fall-out room for up to 14 days after an attack almost without leaving it at all. The government also prepared a recorded announcement which was to have been broadcast by the British Broadcasting Corporation, BBC if a nuclear attack ever did occur. Sirens left over from the London Blitz during World War II were also to be used to warn the public. The system was mostly dismantled in 1992.


Politics


Anti-nuclear movement

The anti-nuclear movement in the United Kingdom consists of groups who oppose nuclear technologies such as nuclear power and
nuclear weapons A nuclear weapon is an explosive device that derives its destructive force from nuclear reactions, either fission (fission bomb) or a combination of fission and fusion reactions ( thermonuclear bomb), producing a nuclear explosion. Both bom ...
. Many different groups and individuals have been involved in anti-nuclear protests, anti-nuclear demonstrations and protests over the years. One of the most prominent anti-nuclear groups in the UK is the Campaign for Nuclear Disarmament (CND). This national movement was founded in the late 1950s, initially in opposition to nuclear testing. It reached its peak around 1960, by which time it had evolved into a broader movement calling for Britain to unilaterally give up nuclear weapons, withdraw from NATO, and end the basing of US bombers armed with nuclear weapons in the UK. The end of atmospheric nuclear testing, internal squabbles, and activists focusing their energies on other causes led to a rapid decline, but it revived in the early 1980s in the wake of the Thatcher government's December 1979 decision to deploy US GLCMs in the UK, and the announcement of its decision to purchase Trident in July 1980. Membership leapt from 3,000 in 1980 to 50,000 a year later, and rallies for unilateral nuclear disarmament in London in October 1981 and June 1982 attracted 250,000 marchers, the largest ever mass demonstrations in the UK up to that time.


End of cross-party support

There was little dissent in the House of Commons from the government's nuclear weapons policy; it had almost bipartisanship (UK), bipartisan support until 1960, with only the Liberal Party (UK), Liberals temporarily dissenting in 1958. Despite opposition from its left wing the Labour party supported British nuclear weapons but opposed tests, and Labour Opposition Leader Hugh Gaitskell and shadow foreign secretary Aneurin Bevan agreed with Sandys on the importance of reducing dependence on the American deterrent. Bevan told his colleagues that their demand for unilateral nuclear disarmament would send a future Labour government "naked into the conference chamber" during international negotiations. From 1955 the government chose to emphasise the nuclear deterrent and de-emphasise conventional forces. In 1962, it stated that the forthcoming Chinese nuclear weapon was a reason for having more than one Western nuclear nation. When France developed its own nuclear weapons, British politicians contended that Europe required an independent deterrent other than that of France. The ''Manchester Guardian'' and other newspapers critical of the Conservative government supported the British deterrent, although it criticised the government for relying on bombers rather than missiles to deliver nuclear weapons. ''The Economist'', the ''New Statesman'', and many left-wing newspapers supported the reliance on nuclear deterrence and nuclear weapons, but in their view considered that of the United States would suffice, and that of the costs of the "nuclear umbrella" was best left to be borne by the United States alone. Gaitskell's Labour party ceased supporting an independent deterrent in 1960 via its new "Policy for Peace", after the cancellation of Blue Streak made nuclear independence less likely. Labour also adopted a resolution favouring unilateral disarmament. Although Gaitskell opposed the resolution and it was reversed in 1961 in favour of continuing support of a general Western nuclear deterrent, the party's opposition to a British deterrent remained and became more prominent. This became a campaign issue during the 1964 United Kingdom general election, 1964 general election. Alec Douglas-Home's incumbent Conservatives stated that the British independent deterrent was necessary for independence from the Americans and maintaining British world influence, and that it was "working for peace" in such cases as the passage of the Nuclear Test Ban Treaty. Led by Gaitskell's successor Harold Wilson, Labour emphasized domestic economic issues and decried the "Tory Nuclear Pretense" as neither independent nor a deterrent. The populace's greater interest in domestic over foreign policy likely contributed more to Labour's victory. The 1982 Labour Party Conference adopted a platform calling for the removal of the GLCMs, the scrapping of Polaris and the cancellation of Trident. This was reaffirmed by the 1986 conference. While the party was given little chance of winning the 1983 election in the aftermath of the Falklands War, polls had shown Labour ahead of the Conservatives in 1986 and 1987. In the wake of Labour's unsuccessful performance in the 1987 United Kingdom general election, 1987 election, the Labour Party leader, Neil Kinnock, despite his own unilateralist convictions, moved to drop the party's disarmament policy, which he saw as a contributing factor in its defeat. The party formally voted to do so in October 1989. Faslane Peace Camp is permanently sited near Faslane naval base, and has been occupied continuously, albeit in different locations, since 12 June 1982. In 2005, there were many protests about the government's proposal to replace the ageing Trident. The largest protest had 100,000 participants and, according to polls, 59 per cent of the public opposed the replacement. In 2006, a year-long protest at Faslane aimed to blockade the base every day for a year. Over a thousand people were arrested. Pro-independence Scottish political parties—the Scottish National Party (SNP), Scottish Green Party, Scottish Socialist Party (SSP) and Solidarity (Scotland), Solidarity—opposed the basing of the Trident system in Scotland, and supported nuclear disarmament. The Radical Independence Campaign political organisation also opposes nuclear weapons and the Trident nuclear weapons programme. Some members and ex-members of the aforementioned political parties, such as Tommy Sheridan and Lloyd Quinan, have taken part in blockades of the Faslane base. In the House of Commons vote in 2007, the majority of Scottish members of parliament voted against upgrading the system, while a substantial majority of English, Welsh and Northern Irish MPs voted in favour. The vote on whether to order the Successor class was held on 18 July 2016 in the House of Commons; the motion passed with a significant majority, extending the programme's life until at least the 2060s. Although 48 Labour MPs voted against it, 41 did not vote, and 140 Labour votes were cast in favour of the motion.


Nuclear posture

The UK relaxed its nuclear posture after the collapse of the Soviet Union. The Labour Party (UK), Labour government's 1998 Strategic Defence Review made reductions from the plans announced by the previous Conservative Party (UK), Conservative government: * The stockpile of "operationally available warheads" was reduced to 225 * The final batch of missile bodies would not be purchased, limiting the fleet to 58. * A submarine's load of warheads was reduced from 96 to 48. This reduced the explosive power of the warheads on a Vanguard class Trident submarine to "one third less than a Polaris submarine armed with Chevaline". However, 48 warheads per Trident submarine represents a 50% increase on the 32 warheads per submarine of Chevaline. Total explosive power has been in decline for decades as the accuracy of missiles has improved, therefore requiring less power to destroy each target. Trident can destroy 48 targets per submarine, as opposed to 32 targets that could be destroyed by Chevaline. * Submarines' missiles would not be targeted, but rather at several days "notice to fire". * Although one submarine would always be on patrol it will operate on a "reduced day-to-day alert state". A major factor in maintaining a constant patrol is to avoid "misunderstanding or escalation if a Trident submarine were to sail during a period of crisis". In April 2017 Defence Secretary Michael Fallon confirmed that the UK would use nuclear weapons in a pre-emptive nuclear strike under "the most extreme circumstances". Until 1998 the aircraft-delivered, free-fall WE.177 bombs provided a sub-strategic option in addition to their designed function as tactical battlefield weapons. With the retirement of WE.177, a sub-strategic warhead is used with some (but not all) deployed Trident missiles. The 2010 Strategic Defence and Security Review further pledged to reduce its requirement for operationally available warheads from fewer than 160 to no more than 120. In a January 2015 written statement, Defence Secretary Michael Fallon reported that "all Vanguard Class SSBNs on continuous at-sea deterrent patrol now carry 40 nuclear warheads and no more than eight operational missiles". However, on 17 March 2021, Prime Minister Boris Johnson announced that the number of nuclear warheads in the UK stockpile would be increased to 260. This reversed the long-term trend of steadily reducing the stockpile.


Nuclear weapons control


Role of the Prime Minister

The Prime Minister authorises the use of nuclear weapons. All former prime ministers have supported an "independent nuclear deterrent", including David Cameron. Only one, James Callaghan, has given any insight on his orders; Callaghan stated that, although in a situation where nuclear weapon use was required – and thus the whole purpose and value of the weapon as a deterrent had failed – he would have ordered use of nuclear weapons, if needed: "if we had got to that point, where it was, I felt it was necessary to do it, then I would have done it (used the weapon) ... but if I had lived after pressing that button, I could have never forgiven myself." Denis Healey, the Secretary of State for Defence and "alternate decision-taker" under Harold Wilson, said that in the event of Soviet nuclear weapons attacking the United Kingdom and the Prime Minister had been killed or incapacitated, he would not have ordered a retaliation. The precise details of how a British Prime Minister would authorise a nuclear strike remain secret, although the principles of the Trident missile control system are believed to be based on the plan set up for Polaris in 1968, which has now been declassified. A closed-circuit television system was set up between 10 Downing Street and the SSBN Control Officer at the Northwood Headquarters of the Royal Navy. Both the Prime Minister and the SSBN Control Officer would be able to see each other on their monitors when the command was given. If the link failed – for instance during a nuclear attack or when the Prime Minister was away from Downing Street – the Prime Minister would send an authentication code which could be verified at Northwood. The Prime Minister would then broadcast a firing order to the SSBN submarines via the Very Low Frequency radio station at Rugby. The UK has not deployed control equipment requiring codes to be sent before weapons can be used, such as the US Permissive Action Link, which if installed would preclude the possibility that military officers could launch British nuclear weapons without authorisation. Until 1998, when it was withdrawn from service, the WE.177 bomb was armed with a standard tubular pin tumbler lock (as used on bicycle locks) and a standard allen key was used to set yield and burst height. Currently, British Trident missile commanders are able to launch their missiles without authorisation, whereas their American counterparts cannot. At the end of the Cold War the US Fail Safe Commission recommended installing devices to prevent rogue commanders persuading their crews to launch unauthorised nuclear attacks. This was endorsed by the Nuclear Posture Review and Trident missile Coded Control Devices were fitted to all US SSBNs by 1997. These devices were designed to prevent an attack until a launch code had been sent by the Joint Chiefs of Staff on behalf of the President. The UK took a decision not to install Trident CCDs or their equivalent on the grounds that an aggressor might be able to wipe out the British chain of command before a launch order had been sent.


Role of the Chief of the Defence Staff

There appears to be a debate over whether concurrence of the Chief of the Defence Staff (United Kingdom), Chief of the Defence Staff is also required to launch a nuclear attack. In December 2008, BBC Radio 4 made a programme titled ''The Human Button'', providing new information on the manner in which the United Kingdom could launch its nuclear weapons, particularly relating to safeguards against a rogue launch. The former Chief of the Defence Staff and Chief of the General Staff (United Kingdom), Chief of the General Staff, General Charles Guthrie, Baron Guthrie of Craigiebank, Lord Guthrie of Craigiebank, explained that the highest level of safeguard was against a prime minister ordering a launch without due cause. The constitutional structure of the United Kingdom provided some protection against such an occurrence, as while the Prime Minister is the chief executive and so practically commands the armed services, the formal commander-in-chief is the British monarchy, monarch, to whom the chief of the defence staff could appeal: "the chief of the defence staff, if he really did think the prime minister had gone mad, would make quite sure that that order was not obeyed ... You have to remember that actually prime ministers give direction, they tell the chief of the defence staff what they want, but it's not prime ministers who actually tell a sailor to press a button in the middle of the Atlantic. The armed forces are loyal, and we live in a democracy, but actually their ultimate authority is the Elizabeth II, Queen." The same interview pointed out that while the Prime Minister would have the constitutional authority to fire the Chief of the Defence Staff, he could not appoint a replacement as the position is appointed by the monarch. The programme also addressed the workings of the system; detailing that two-man rule, two persons are required to authenticate each stage of the process before launching, with the submarine captain only able to access the firing trigger after two safes have been opened with keys held by the ship's executive and weapons engineering officers. Another (albeit partly challenged) explanation is that while the Prime Minister can give an authorisation, only commissioned officers of the British Armed Forces, armed forces (like the Chief of the Defence Staff) can give an order.


Nuclear deputies

The Prime Minister appoints nuclear deputies in case they are out of reach or indisposed during an emergency. Such appointments are made on a personal basis rather than according to the ministerial ranking. In 1961, the Prime Minister was advised for the first time to appoint a first deputy and second deputy to authorise nuclear retaliation if they were not immediately available. In 1961, Harold Macmillan chose Rab Butler and Selwyn Lloyd (in that order), replacing Lloyd with Alec Douglas-Home in 1962. In 1964, Douglas-Home finally got around to appointing Butler and Lloyd (though Peter Thorneycroft instead of Lloyd was considered before this) as his first and second nuclear deputies, respectively. In 1965, Wilson chose Bert Bowden as his first deputy and Healey as his second deputy. Michael Stewart, Baron Stewart of Fulham, Michael Stewart took over from Bowden as first deputy in 1966. Edward Heath chose Reginald Maudling, Douglas-Home and Peter Carington, 6th Baron Carrington, Lord Carrington as his nuclear deputies in 1970. In 1974, Wilson made Callaghan first deputy and Healey second deputy. When Callaghan became Prime Minister in 1976, he made Healey first deputy and Roy Mason second deputy. It does not seem that the files on who Margaret Thatcher (and subsequent premiers) appointed to the role have been released yet. The practice of appointing nuclear deputies apparently fell out of practice between the end of the Cold War and 2001 when, following the September 11 attacks, Blair revived the practice, but Rifkind has revealed that he was nominated by John Major in 1995 as one of the two nuclear deputies "to act on his behalf in the event of either his death or incapacity at a time of grave crisis for this country."


Letters of last resort

During the Cold War, if a nuclear attack had taken place and the Prime Minister and their deputies could not be obtained, then Royal Air Force Strike Command had standing delegated authority to retaliate. Since 1972, the Prime Minister has also written four letters of last resort, one for each SSBN commander. The Prime Minister writes these letters when they take office and they set out what the commander should do in the event of a nuclear attack that kills the Prime Minister and their nuclear deputy/ies. Past options proposed to the Prime Minister have included commit the forces, do not commit the forces, make the most reasonable choice or place yourself under Allied command. This system of issuing notes containing orders in the event of the head of government's death is said to be unique to the United Kingdom (although the concept of written last orders, particularly of a ship's captain, is a naval tradition), with other nuclear powers using different procedures. The letters are destroyed unopened whenever a Prime Minister leaves office.


Legality

The United Kingdom is one of the five nuclear-weapon states legally recognised as such under the
Treaty on the Non-Proliferation of Nuclear Weapons The Treaty on the Non-Proliferation of Nuclear Weapons, commonly known as the Non-Proliferation Treaty or NPT, is an international treaty whose objective is to prevent the spread of nuclear weapons and weapons technology, to promote cooperation ...
(NPT). , nine countries have nuclear weapons. After the UK government announced its plans to refurbish its Trident missiles and build new submarines to carry them, it published a white paper on ''The Future of the United Kingdom's Nuclear Deterrent'', in which it stated that the renewal is fully compatible with the United Kingdom's treaty commitments and international law. At the start of the British House of Commons, House of Commons debate to authorise the replacement of Trident, Margaret Beckett, the Secretary of State for Foreign and Commonwealth Affairs, stated: The subsequent vote was won overwhelmingly, including unanimous support from the opposition Conservative Party. The Government's position remained that it was abiding by the NPT in renewing Trident, and Britain has the right to possess nuclear weapons, a position reiterated by Tony Blair on 21 February 2007. Only the United Kingdom has expressed its opposition to the establishment of a new legally binding treaty to prevent the threat or use of nuclear weapons against non-nuclear states, through its vote in the United Nations General Assembly in 1998. The United Kingdom decided not to sign the UN treaty on the Prohibition of Nuclear Weapons, a binding agreement for negotiations for the total elimination of nuclear weapons, supported by more than 120 nations. None of the nine countries known or believed at the time to possess nuclear weapons supported the treaty, nor did any of the 30 countries of the NATO alliance.


Notes


References

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Further reading

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External links


British Nuclear Weapons Stockpile, 1953–2013
a
History in Pieces
* Video archive of th
UK's Nuclear Testing
a
sonicbomb.com


BASIC


''The Real Meaning of the Words: a Pedantic Glossary of British Nuclear Weapons''
(PDF) {{DEFAULTSORT:Nuclear Weapons And The United Kingdom Nuclear history of the United Kingdom, Nuclear weapons programme of the United Kingdom, Articles containing video clips