Commander Commander (commonly abbreviated as Cmdr.) is a common naval officer rank. Commander is also used as a rank or title in other formal organizations, including several police forces. In several countries this naval rank is termed frigate captain. ...

Alexander "Alastair" Guthrie Denniston (1 December 1881 – 1 January 1961) was a Scottish codebreaker in Room 40, deputy head of the

Government Code and Cypher School Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the Uni ...

(GC&CS) and

hockey Hockey is a term used to denote a family of various types of both summer and winter team sports which originated on either an outdoor field, sheet of ice, or dry floor such as in a gymnasium. While these sports vary in specific rules, numbers o ...

player. Denniston was appointed operational head of GC&CS in 1919 and remained so until February 1942.F. H. Hinsley, revised by Ralph Erskine, "Denniston, Alexander Guthrie lastair(1881–1961), cryptanalyst and intelligence officer", ''

Oxford Dictionary of National Biography The ''Dictionary of National Biography'' (''DNB'') is a standard work of reference on notable figures from British history, published since 1885. The updated ''Oxford Dictionary of National Biography'' (''ODNB'') was published on 23 September ...

'', 2004

Early life

Denniston was born in

Greenock Greenock (; sco, Greenock; gd, Grianaig, ) is a town and administrative centre in the Inverclyde council area in Scotland, United Kingdom and a former burgh within the historic county of Renfrewshire, located in the west central Lowland ...

Renfrewshire Renfrewshire () ( sco, Renfrewshire; gd, Siorrachd Rinn Friù) is one of the 32 council areas of Scotland. Located in the west central Lowlands, it is one of three council areas contained within the boundaries of the historic county of Re ...

, the son of a medical practitioner. He studied at the

University of Bonn The Rhenish Friedrich Wilhelm University of Bonn (german: Rheinische Friedrich-Wilhelms-Universität Bonn) is a public research university located in Bonn, North Rhine-Westphalia, Germany. It was founded in its present form as the ( en, Rhine ...

and the

University of Paris , image_name = Coat of arms of the University of Paris.svg , image_size = 150px , caption = Coat of Arms , latin_name = Universitas magistrorum et scholarium Parisiensis , motto = ''Hic et ubique terrarum'' (Latin) , mottoeng = Here and a ...

. Denniston was a member of the Scottish Olympic hockey team in 1908 and won a bronze medal. He played as a half-back, and his club team was listed as Edinburgh. In the IOC's official 1908 report, he is listed as Dennistoun rather than Denniston.

First World War and interbellum

In 1914 Denniston helped form Room 40 in the Admiralty, an organisation responsible for intercepting and decrypting enemy messages. In 1917 he married a fellow Room 40 worker, Dorothy Mary Gilliat. After

First World War World War I (28 July 1914 11 November 1918), often abbreviated as WWI, was List of wars and anthropogenic disasters by death toll, one of the deadliest global conflicts in history. Belligerents included much of Europe, the Russian Empire, ...

, Denniston, recognising the strategic importance of codebreaking, kept the Room 40 activity functioning. Room 40 was merged with its counterpart in the Army,

MI1b MI1 or British ''Military Intelligence, Section 1'' was a department of the British Directorate of Military Intelligence, part of the War Office. It was set up during World War I. It contained "C&C", which was responsible for code breaking. I ...

in 1919, renamed the Government Code and Cypher School (GC&CS) in 1920 and transferred from the Navy to the Foreign Office. Denniston was chosen to run the new organisation. With the rise of

Hitler Adolf Hitler (; 20 April 188930 April 1945) was an Austrian-born German politician who was dictator of Nazi Germany, Germany from 1933 until Death of Adolf Hitler, his death in 1945. Adolf Hitler's rise to power, He rose to power as the le ...

, Denniston began making preparations. Following the practice of his superiors at Room 40, he contacted scientists from Oxford and Cambridge (including

Alan Turing Alan Mathison Turing (; 23 June 1912 – 7 June 1954) was an English mathematician, computer scientist, logician, cryptanalyst, philosopher, and theoretical biologist. Turing was highly influential in the development of theoretical ...

and

Gordon Welchman William Gordon Welchman (15 June 1906 – 8 October 1985) was a British mathematician. During World War II, he worked at Britain's secret codebreaking centre, "Station X" at Bletchley Park, where he was one of the most important contributors. ...

) asking if they would be willing to serve if war broke out.

Bletchley Park Bletchley Park is an English country house and estate in Bletchley, Milton Keynes (Buckinghamshire) that became the principal centre of Allied code-breaking during the Second World War. The mansion was constructed during the years following ...

was chosen by MI6 chief Admiral

Hugh Sinclair Admiral Sir Hugh Francis Paget Sinclair, (18 August 1873 – 4 November 1939), known as Quex Sinclair, was a British intelligence officer. He was Director of British Naval Intelligence between 1919 and 1921, and he subsequently helped to set ...

as the location for the codebreaking effort because it was at a

rail junction A junction, in the context of rail transport, is a place at which two or more rail routes converge or diverge. This implies a physical connection between the tracks of the two routes (assuming they are of the same gauge), provided by ''points'' ( ...

on the west coast main line north of London with good rail connections to Oxford and Cambridge. Sinclair acquired the

property and Denniston was assigned to prepare the site and design the huts to be built on the grounds. The GC&CS moved to the new location in August 1939, just before the

Invasion of Poland The invasion of Poland (1 September – 6 October 1939) was a joint attack on the Republic of Poland by Nazi Germany and the Soviet Union which marked the beginning of World War II. The German invasion began on 1 September 1939, one week af ...

and the start of the

Second World War World War II or the Second World War, often abbreviated as WWII or WW2, was a world war that lasted from 1939 to 1945. It involved the vast majority of the world's countries—including all of the great powers—forming two opposi ...

. Its name changed to

Government Communications Headquarters Government Communications Headquarters, commonly known as GCHQ, is an intelligence and security organisation responsible for providing signals intelligence (SIGINT) and information assurance (IA) to the government and armed forces of the Uni ...

(GCHQ). On 26 July 1939, five weeks before the outbreak of war, Denniston was one of three Britons (along with

Dilly Knox Alfred Dillwyn "Dilly" Knox, CMG (23 July 1884 – 27 February 1943) was a British classics scholar and papyrologist at King's College, Cambridge and a codebreaker. As a member of the Room 40 codebreaking unit he helped decrypt the Zimm ...

and Humphrey Sandwith) who participated in the trilateral Polish-French-British conference held in the Kabaty Woods south of

Warsaw Warsaw ( pl, Warszawa, ), officially the Capital City of Warsaw,, abbreviation: ''m.st. Warszawa'' is the capital and largest city of Poland. The metropolis stands on the River Vistula in east-central Poland, and its population is officiall ...

, at which the Polish

Biuro Szyfrów The Cipher Bureau, in Polish: ''Biuro Szyfrów'' (), was the interwar Polish General Staff's Second Department's unit charged with SIGINT and both cryptography (the ''use'' of ciphers and codes) and cryptanalysis (the ''study'' of ciphers and co ...

(Cipher Bureau) initiated the French and British into the

decryption In cryptography, encryption is the process of encoding information. This process converts the original representation of the information, known as plaintext, into an alternative form known as ciphertext. Ideally, only authorized parties can deci ...

German German(s) may refer to: * Germany (of or related to) **Germania (historical use) * Germans, citizens of Germany, people of German ancestry, or native speakers of the German language ** For citizens of Germany, see also German nationality law **Ge ...

military

Enigma Enigma may refer to: *Riddle, someone or something that is mysterious or puzzling Biology *ENIGMA, a class of gene in the LIM domain Computing and technology * Enigma (company), a New York-based data-technology startup * Enigma machine, a family ...

cipher In cryptography, a cipher (or cypher) is an algorithm for performing encryption or decryption—a series of well-defined steps that can be followed as a procedure. An alternative, less common term is ''encipherment''. To encipher or encode ...

Second World War

Denniston remained in command until he was hospitalised in June 1940 for a

bladder stone A bladder stone is a stone found in the urinary bladder. Signs and symptoms Bladder stones are small mineral deposits that can form in the bladder. In most cases bladder stones develop when the urine becomes very concentrated or when one is ...

. Despite his illness, he flew to the United States in 1941 to make contact with American cryptographers including William Friedman. Denniston returned to Bletchley Park for a while but moved to London later in 1941 to work on diplomatic traffic. Despite his knowledge of the success of Polish cryptologists against Enigma, Denniston shared the general pessimism about the prospects of breaking the more complex Naval Enigma encryption until as late as the summer of 1940, having told the Head of Naval Section at Bletchley: "You know, the Germans don't mean you to read their stuff, and I don't expect you ever will." The advent of

Banburismus Banburismus was a cryptanalytic process developed by Alan Turing at Bletchley Park in Britain during the Second World War. It was used by Bletchley Park's Hut 8 to help break German ''Kriegsmarine'' (naval) messages enciphered on Enigma machin ...

shortly afterwards showed his pessimism to be misplaced. In October 1941, the originator of the technique,

, along with fellow senior cryptologists

, Stuart Milner-Barry and Hugh Alexander wrote to Churchill, over the head of Denniston, to alert Churchill to the fact that a shortage of staff at Bletchley Park was preventing them from deciphering many messages. An addition of personnel, small by military standards, could make a big difference to the effectiveness of the fighting effort. The slow response to previous requests had convinced them that the strategic value of their work was not understood in the right quarters. In the letter, there was praise for the 'energy and foresight' of Commander

Edward Travis Sir Edward Wilfred Harry Travis (24 September 1888 – 23 April 1956) was a British cryptographer and intelligence officer, becoming the operational head of Bletchley Park during World War II, and later the head of GCHQ. Career Educated loc ...

. Churchill reacted to the letter immediately, ordering "Action this day". Resources were transferred as fast as possible. In February 1942, GC&CS was reorganised. Travis, Denniston's second in command and chief of the Naval section, succeeded Denniston at Bletchley Park, overseeing the work on military codes and ciphers. When Travis took over, he "presided over an administrative revolution which at last brought the management of Intelligence into line with its mode of production".

Personal and post-war life

Denniston and his wife had two children: a son and daughter. Their son,

Robin Robin may refer to: Animals * Australasian robins, red-breasted songbirds of the family Petroicidae * Many members of the subfamily Saxicolinae (Old World chats), including: **European robin (''Erithacus rubecula'') ** Bush-robin **Forest r ...

, was educated at

Westminster School (God Gives the Increase) , established = Earliest records date from the 14th century, refounded in 1560 , type = Public school Independent day and boarding school , religion = Church of England , head_label = Hea ...

and

Christ Church, Oxford Christ Church ( la, Ædes Christi, the temple or house, '' ædēs'', of Christ, and thus sometimes known as "The House") is a constituent college of the University of Oxford in England. Founded in 1546 by King Henry VIII, the college is uniq ...

. After Alastair's demotion and resulting decreased income, Robin's school fees were paid by benefactors. However, the Dennistons' daughter had to leave her school due to lack of funds. Denniston retired in 1945, and later taught French and Latin in

Leatherhead Leatherhead is a town in the Mole Valley District of Surrey, England, about south of Central London. The settlement grew up beside a ford on the River Mole, from which its name is thought to derive. During the late Anglo-Saxon period, Leathe ...

. William Friedman, the American cryptographer who broke the Japanese Purple code, later wrote to Denniston's daughter "Your father was a great man in whose debt all English-speaking people will remain for a very long time, if not forever. That so few should know exactly what he did ... is the sad part." Robin distinguished himself as a publisher. In 2007, he published ''Thirty Secret Years'', a biography of his father that consolidated his reputation in GCHQ history.

Honours and awards

*7 January 1918 appointed an Officer of the Order of the British Empire (OBE) ''Commander Alexander Guthrie Denniston, R.N.V.R. Naval Intelligence Division, Admiralty.'' *2 January 1933 appointed a Commander of the Order of the British Empire (CBE) ''Commander Alexander Guthrie Denniston, O.B.E., R.N.V.R. Head of a Department, Foreign Office.'' *12 June 1941 appointed a Companion of the Order of St Michael and St George (CMG) ''Commander Alexander Guthrie Denniston, C.B.E., R.N.V.R. (Retd.), Head of a Department of the Foreign Office''.

Fictional depictions

In the 2014 film '' The Imitation Game'', he is portrayed by

Charles Dance Walter Charles Dance (born 10 October 1946) is an English actor. He is known for playing strict, authoritarian characters and villains. His most notable film roles include Sardo Numspa in '' The Golden Child'' (1986), Dr. Jonathan Clemens in '' ...

References

Bibliography

* Robin Denniston Churchill's Secret War: Diplomatic Decrypts, the Foreign Office and Turkey 1942–44 (1997) * James Gannon, ''Stealing Secrets, Telling Lies: How Spies and Codebreakers Helped Shape the Twentieth Century'', Washington, D.C., Brassey's, 2001, . * F. H. Hinsley and

Alan Stripp Alan may refer to: People *Alan (surname), an English and Turkish surname *Alan (given name), an English given name **List of people with given name Alan ''Following are people commonly referred to solely by "Alan" or by a homonymous name.'' * A ...

, eds., ''Codebreakers: the Inside Story of Bletchley Park'', Oxford University Press, 1993, . * Władysław Kozaczuk, ''Enigma: How the German Machine Cipher Was Broken and How It Was Read by the Allies in World War II'', edited and translated by

Christopher Kasparek Christopher Kasparek (born 1945) is a Scottish-born writer of Polish descent who has translated works by numerous authors, including Ignacy Krasicki, Bolesław Prus, Florian Znaniecki, Władysław Tatarkiewicz, Marian Rejewski, and Władysław ...

, Frederick, MD, University Publications of America, 1984, , pp. 59–60.

External links

The Papers of Alexander Guthrie Denniston
are held at the

Churchill Archives Centre The Churchill Archives Centre (CAC) at Churchill College at the University of Cambridge is one of the largest repositories in the United Kingdom for the preservation and study of modern personal papers. It is best known for housing the papers of ...

in Cambridge, and are accessible to the public.
DatabaseOlympics.com profileThirty Secret Years: A.G. Denniston's work in signals intelligence 1914-1944
{{DEFAULTSORT:Denniston, Alastair British cryptographers Pre-computer cryptographers Bletchley Park people 1881 births 1961 deaths British people of World War I British people of World War II Royal Navy officers Commanders of the Order of the British Empire Companions of the Order of St Michael and St George GCHQ Scottish male field hockey players Olympic bronze medallists for Great Britain Olympic medalists in field hockey Olympic field hockey players of Great Britain British male field hockey players Field hockey players at the 1908 Summer Olympics University of Bonn alumni University of Paris alumni People from Greenock Medalists at the 1908 Summer Olympics Scottish Olympic medallists Foreign Office personnel of World War II British expatriates in France