Martin-Baker Aircraft Company Limited is a British manufacturer of
ejection seat
In aircraft, an ejection seat or ejector seat is a system designed to rescue the aircraft pilot, pilot or other aircrew, crew of an aircraft (usually military) in an emergency. In most designs, the seat is propelled out of the aircraft by an ex ...
s and safety-related equipment for aviation. The company's origins were originally as an aircraft manufacturer before becoming a pioneer in the field of ejection seats. The company's headquarters are in
Higher Denham,
Buckinghamshire
Buckinghamshire (), abbreviated Bucks, is a ceremonial county in South East England that borders Greater London to the south-east, Berkshire to the south, Oxfordshire to the west, Northamptonshire to the north, Bedfordshire to the north-ea ...
,
England
England is a country that is part of the United Kingdom. It shares land borders with Wales to its west and Scotland to its north. The Irish Sea lies northwest and the Celtic Sea to the southwest. It is separated from continental Europe b ...
, with other sites in
France
France (), officially the French Republic ( ), is a country primarily located in Western Europe. It also comprises of Overseas France, overseas regions and territories in the Americas and the Atlantic Ocean, Atlantic, Pacific Ocean, Pac ...
,
Italy
Italy ( it, Italia ), officially the Italian Republic, ) or the Republic of Italy, is a country in Southern Europe. It is located in the middle of the Mediterranean Sea, and its territory largely coincides with the homonymous geographical re ...
and 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 primarily located in North America. It consists of 50 states, a federal district, five major unincorporated territorie ...
.
Martin-Baker supplies ejection seats for 93 air forces worldwide.
["Martin-Basker: About."](_blank)
''Martin-Baker.'' Retrieved: 31 October 2012. Martin-Baker seats have been fitted into over 200 fixed-wing and rotary types with the most recent being the
Lockheed Martin F-35 Lightning II
The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, all-weather stealth multirole combat aircraft that is intended to perform both air superiority and strike missions. It is also able to provide ele ...
programme.
Martin-Baker claimed in 2022 that since the first live ejection test in 1945, a total of 7,674 lives have been saved by the company's ejection seats.
Martin-Baker also manufactures what it calls "crashworthy" seats for helicopters and fixed-wing aircraft. , over 20,000 crashworthy seats have been delivered. The Martin-Baker company continues as a family-run business, run by the twin sons of the late
Sir James Martin since Autumn 1979.
History
"Martin's Aircraft Works" was founded at Denham by
James Martin and
Captain Valentine Baker with financial help from Francis Francis. The company was building a prototype aircraft, the MB 1, using the design patents for aircraft structures held by Martin. On 17 August 1934, the Martin-Baker Aircraft Company was formed to continue the work of aircraft development.
["Martin-Baker: History and developments."](_blank)
''Martin-Baker.'' Retrieved: 31 October 2012.
Martin and Baker designed an unconventional, two-seat, low-wing monoplane design in the early 1930s as the MB 1. This was powered by a
de Havilland Gipsy
The de Havilland Gipsy is a British air-cooled four-cylinder in-line aircraft engine designed by Frank Halford in 1927 to replace the ADC Cirrus in the de Havilland DH.60 Moth light biplane. Initially developed as an upright 5 litre (300 ...
engine mounted in the fuselage behind the seats and driving a fixed pitch propeller through a shaft running horizontally between the pilot and passenger. The project was abandoned due to financial constraints, although the fuselage and engine installation had been completed. Martin-Baker also constructed an
autogyro
An autogyro (from Greek and , "self-turning"), also known as a ''gyroplane'', is a type of rotorcraft that uses an unpowered rotor in free autorotation to develop lift. Forward thrust is provided independently, by an engine-driven propeller. Whi ...
designed by
Raoul Hafner
Raoul Hafner, (1905–1980) FEng, FRAes, was an Austrian-born British helicopter pioneer and engineer. He made a distinctive contribution to the British aerospace industry, particularly in the development of helicopters.
Life
Born in 1905, he ...
. This, their first complete aircraft project, was later tested by Captain Baker at
Heston Aerodrome
Heston Aerodrome was an airfield located to the west of London, England, operational between 1929 and 1947. It was situated on the border of the Heston and Cranford areas of Hounslow, Middlesex. In September 1938, the British Prime Minister, Ne ...
.
In 1935, Martin and Baker designed and flew their
Martin-Baker MB 1
The Martin-Baker MB 1 was a British low-wing light aircraft, designed and constructed in the 1930s, the first aircraft design of the Martin-Baker company to be built. While not a fighter itself, the design would heavily influence Martin-Baker ...
, a two-seat light touring aircraft. Their first military design was the
Martin-Baker MB 2
The Martin-Baker MB 2 was a British private-venture fighter prototype based on a simple basic structure that had been developed in the earlier MB 1 civil aircraft. Although briefly evaluated as a fighter by the Royal Air Force, the MB 2 was li ...
, a
Napier Dagger
The Napier Dagger was a 24-cylinder H-pattern ''(or H-Block)'' air-cooled engine designed by Frank Halford and built by Napier before World War II. It was a development of the earlier Napier Rapier.
Design and development
The H-Block has a ...
–powered fighter that flew in 1938. It was a private venture to meet
Air Ministry Specification
This is a partial list of the British Air Ministry (AM) specifications for aircraft. A specification stemmed from an Operational Requirement, abbreviated "OR", describing what the aircraft would be used for. This in turn led to the specification i ...
F.5/34 for a fighter for service in the tropics. The MB 2 was tested but neither it nor other designs to F.5/34 were adopted.
*
Martin-Baker MB 3
The Martin-Baker MB 3 was a British prototype fighter aircraft, developed from Martin-Baker’s earlier private ventures, the MB 1 and the MB 2. The design was notable for its heavy armament of six 20 mm Hispano cannons. The fatal cra ...
(1942): a six-cannon fighter design, powered by a
Napier Sabre
The Napier Sabre is a British H-24-cylinder, liquid-cooled, sleeve valve, piston aero engine, designed by Major Frank Halford and built by D. Napier & Son during World War II. The engine evolved to become one of the most powerful inline ...
. Baker was killed in a crash while testing the prototype.
* Martin-Baker MB 4 (1943): a
Rolls-Royce Griffon
The Rolls-Royce Griffon is a British 37-litre (2,240 cu in) capacity, 60-degree V-12, liquid-cooled aero engine designed and built by Rolls-Royce Limited. In keeping with company convention, the Griffon was named after a bird of prey, ...
-engined fighter, cancelled on the drawing board.
The
Martin-Baker MB 5
The British Martin-Baker MB 5 was the ultimate development of a series of prototype fighter aircraft built during the Second World War. Neither the MB 5 nor its predecessors ever entered production, despite what test pilots described as excelle ...
which first flew in 1944 had started out as the second MB 3 prototype but was extensively redesigned with a tubular steel fuselage. It used the Griffon engine driving contra-rotating propellers.
* Martin-Baker MB 6 (1945): a Second World War jet fighter project with a swing-arm, 0/0 spring-loaded ejection seat.
* Martin-Baker MB 7 (1946) ''Black Bess'': a postwar interceptor/high-speed test aircraft concept. Small flying models were made but the concept was cancelled in 1947.
Martin-Baker manufactured aircraft components, including retrofit improvements to the ammunition belt feeds for the
Hispano Mk II autocannon and armoured seats for
Supermarine Spitfire
The Supermarine Spitfire is a British single-seat fighter aircraft used by the Royal Air Force and other Allied countries before, during, and after World War II. Many variants of the Spitfire were built, from the Mk 1 to the Rolls-Royce Grif ...
s, throughout the Second World War. James Martin also designed and manufactured explosive bolt cutters fitted to bomber wings to cut barrage balloon cables that were fitted to many aircraft and saved a number of aircraft.
In 1944, the company was approached by the
Ministry of Aircraft Production
Ministry may refer to:
Government
* Ministry (collective executive), the complete body of government ministers under the leadership of a prime minister
* Ministry (government department), a department of a government
Religion
* Christian ...
to investigate ejection systems enabling pilots to bail out safely from high-speed fighter aircraft.
Ejection seats
![MBakerMkGT5Left](https://upload.wikimedia.org/wikipedia/commons/b/b4/MBakerMkGT5Left.JPG)
Martin-Baker investigated ejection seats from 1934 onwards, several years before Germany and Sweden proposed similar systems in 1938. The company concluded that an explosive-powered ejection seat was the best solution. In particular, Baker's death in 1942 during a test flight of the MB 3 affected Martin so much that pilot safety became his primary focus and led to the later reorganisation of the company to focus primarily on ejection seats.
In 1944, James Martin was asked by the
Ministry of Aircraft Production
Ministry may refer to:
Government
* Ministry (collective executive), the complete body of government ministers under the leadership of a prime minister
* Ministry (government department), a department of a government
Religion
* Christian ...
to develop methods for fighter pilots to escape their aircraft.
Martin decided that the best method involved ejection of the seat with the occupant sitting in it, aided by an explosive charge. After ejection, the pilot would separate from the seat and open his parachute by pulling a ripcord in the usual way.
At that time there was little information on how much upward thrust the human body could withstand. Data relating to "g" forces in catapult launching of aircraft involved horizontal thrust and was therefore inapplicable to the new problem. Tests would have to be conducted to find out how much upward "g" force a person could tolerate. These were done by shooting a seat up a near-vertical path, loading the seat to represent the weight of the occupant, and measuring the accelerations involved.
A 16-foot (5-metre) test rig was built in the form of a tripod, one of the legs being in the form of guide rails. The seat was propelled up the guide rails by a gun, consisting of two telescopic tubes energised by an explosive cartridge. The guide rails were provided with ratchet stops every three inches (75 mm), so that the seat was automatically arrested at the top of its travel.
Studies were conducted to find the limits of upward acceleration that the human body could stand. The first dummy shot with the seat loaded to 200 lb was made on 20 January 1945, and four days later one of the company's experimental
fitters, Bernard Lynch, undertook the first "live" ride, being shot up the rig to a height of 4 feet 8 inches. In three further tests, the power of the cartridge was progressively increased until a height of 10 feet was reached, at which stage Lynch reported the onset of considerable physical discomfort. The first seat was successfully live-tested by Lynch on 24 July 1946, who ejected from a
Gloster Meteor
The Gloster Meteor was the first British jet fighter and the Allies of World War II, Allies' only jet aircraft to engage in combat operations during the Second World War. The Meteor's development was heavily reliant on its ground-breaking turb ...
travelling at
IAS IAS may refer to:
Science
* Institute for Advanced Study, in Princeton, New Jersey, United States
* Image Analysis & Stereology, the official journal of the International Society for Stereology & Image Analysis.
* Iowa Archeological Society, Uni ...
at over
Chalgrove Airfield
Chalgrove Airfield is a former Second World War airfield in Oxfordshire, England. It is approximately north-northeast of Benson, Oxfordshire, Benson in the heart of South Oxfordshire between Henley and Oxford; about north-northwest of London. ...
in
Oxfordshire
Oxfordshire is a ceremonial and non-metropolitan county in the north west of South East England. It is a mainly rural county, with its largest settlement being the city of Oxford. The county is a centre of research and development, primarily ...
.
The first production Martin-Baker ejection seat, a '
Pre-Mk 1', was installed in the
Saunders-Roe SR.A/1 prototype.
The first use of an ejection seat in a practical application by a British pilot involved the
Armstrong Whitworth A.W.52
The Armstrong Whitworth A.W.52 was an early flying wing aircraft designed and produced by British aircraft manufacturer Armstrong Whitworth Aircraft.
The A.W.52 emerged out of wartime research into the laminar flow airfoil, which indicated th ...
flying wing experimental aircraft in May 1949.
Martin-Baker was a pioneer in expanding the operational envelope of the ejection seat to enable it to be used at low altitudes and airspeeds, leading eventually to development of the "
zero-zero" capability in 1961.
Applications
Martin-Baker Mk.1
Martin-Baker Mk.2
Martin-Baker Mk.3
Martin-Baker Mk.4
Martin-Baker Mk.5
Martin-Baker Mk.6
Martin-Baker Mk.7
Martin-Baker Mk.8
*
Embraer EMB 312 Tucano
The Embraer EMB 312 Tucano (English: ''Toucan'') is a low-wing, tandem-seat, single-turboprop, basic trainer with counter-insurgency capability that was developed in Brazil. The Brazilian Air Force sponsored the EMB-312 project at the end of ...
*
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 ...
Martin-Baker Mk.9
*
Dornier Do 31
The Dornier Do 31 is an experimental vertical take-off and landing (VTOL) jet-propelled transport designed and produced by West German aircraft manufacturer Dornier.
The development of the Do 31 was motivated principally by heavy interest expre ...
*
Hawker Siddeley Harrier
The Hawker Siddeley Harrier is a British military aircraft. It was the first of the Harrier series of aircraft and was developed in the 1960s as the first operational ground attack and reconnaissance aircraft with vertical/short takeoff and ...
*
Nord 500
*
SEPECAT Jaguar
The SEPECAT Jaguar is an Anglo-French jet attack aircraft originally used by the British Royal Air Force and the French Air Force in the close air support and nuclear strike role. It is still in service with the Indian Air Force.
Originall ...
*
VFW VAK 191B
The VFW VAK 191B was an experimental German vertical take-off and landing (VTOL) strike fighter of the early 1970s. VAK was the abbreviation for ''Vertikalstartendes Aufklärungs- und Kampfflugzeug'' (Vertical Take-off Reconnaissance and Strike ...
Martin-Baker Mk.10
Martin-Baker Mk.11
*
Pilatus PC-7 Turbo Trainer
The Pilatus PC-7 Turbo Trainer is a low-wing tandem-seat training aircraft designed and manufactured by Pilatus Aircraft of Switzerland. The aircraft is capable of all basic training functions including aerobatics, instrument, tactical and nig ...
*
Pilatus PC-9
The Pilatus PC-9 is a single-engine, low-wing tandem-seat turboprop training aircraft manufactured by Pilatus Aircraft of Switzerland. Designed as a more powerful evolution of the Pilatus PC-7, the PC-9's first flight was made in May 1984 after ...
*
PZL-130TC Orlik
Martin-Baker Mk.12
*Hawker Siddeley Harrier
Martin-Baker Mk.14 NACES (SJU-17)
This ejection seat is used by the
US Navy
The United States Navy (USN) is the maritime service branch of the United States Armed Forces and one of the eight uniformed services of the United States. It is the largest and most powerful navy in the world, with the estimated tonnage of ...
and is often designated Martin-Baker NACES (Naval Aircrew Ejection Seat) SJU-17 with a suffix letter for the different variants.
*
Grumman F-14D Tomcat
*
McDonnell Douglas F/A-18 Hornet
The McDonnell Douglas F/A-18 Hornet is an all-weather, twin-engine, supersonic, carrier-capable, multirole combat aircraft, designed as both a fighter and attack aircraft (hence the F/A designation). Designed by McDonnell Douglas (now p ...
*
McDonnell Douglas T-45 Goshawk
The McDonnell Douglas (now Boeing) T-45 Goshawk is a highly modified version of the British BAE Systems Hawk land-based training jet aircraft. Manufactured by McDonnell Douglas (now Boeing) and British Aerospace (now BAE Systems), the T-45 is u ...
Martin-Baker Mk.15
*
Pilatus PC-7 Mk II
*
UTVA Kobac
The UTVA Kobac (English: ''Sparrowhawk'') was a prototype Serbian single-engine, low-wing tandem-seat turboprop training/light attack aircraft manufactured by Pančevo based UTVA Aviation Industry and designed by the Military Technical Institu ...
Martin-Baker Mk.16
*
Alenia Aermacchi M-346 Master
The Aermacchi M-346 Master is a family of military twin-engine transonic advanced jet trainers and light combat aircraft. Originally co-developed with Yakovlev as the Yak/AEM-130, the partnership was dissolved in 2000 and then Alenia Aermacchi ...
*
Beechcraft T-6 Texan II
The Beechcraft T-6 Texan II is a single-engine turboprop aircraft built by the Raytheon Aircraft Company (Textron Aviation since 2014). A trainer aircraft based on the Pilatus PC-9, the T-6 has replaced the United States Air Force's Cessna T ...
*
Dassault Rafale
The Dassault Rafale (, literally meaning "gust of wind", and "burst of fire" in a more military sense) is a French twin-engine, canard delta wing, multirole fighter aircraft designed and built by Dassault Aviation. Equipped with a wide ran ...
*
Eurofighter Typhoon
The Eurofighter Typhoon is a European multinational twin-engine, canard delta wing, multirole fighter. The Typhoon was designed originally as an air-superiority fighter and is manufactured by a consortium of Airbus, BAE Systems and Leonardo ...
*
TAI Hürkuş
The TAI Hürkuş ''(Free Bird)'' is a tandem two-seat, low-wing, single-engine, turboprop aircraft being developed by Turkish Aerospace Industries (TAI) as a new Trainer (aircraft), basic trainer and ground attack aircraft for the Turkish Armed ...
*
Lockheed Martin F-35 Lightning II
The Lockheed Martin F-35 Lightning II is an American family of single-seat, single-engine, all-weather stealth multirole combat aircraft that is intended to perform both air superiority and strike missions. It is also able to provide ele ...
*
Northrop T-38 Talon
The Northrop T-38 Talon is a two-seat, twinjet supersonic jet trainer. It was the world's first, and the most produced, supersonic trainer. The T-38 remains in service in several air forces.
The United States Air Force (USAF) operates the most ...
*
Pilatus PC-21
The Pilatus PC-21 is a turboprop-powered advanced trainer with a stepped tandem cockpit. It is manufactured by Pilatus Aircraft of Switzerland.
Development
In November 1997 Pilatus flew a modified PC-7 Mk.II in order to test improvements for ...
*
HAL Tejas
The HAL Tejas is an Indian, single engine, delta wing, light multirole fighter designed by the Aeronautical Development Agency (ADA) in collaboration with Aircraft Research and Design Centre (ARDC) of Hindustan Aeronautics Limited (HAL) for t ...
Martin-Baker Mk.17
Extremely compact and lightweight ejection seat designed with minimise mass and maintenance. Most lightweight ejection seat in Martin-Baker inventory.
*
Grob G 120TP
The Grob G 120TP is a two-seat turboprop training and aerobatic low-wing aircraft with a composite airframe, built by Grob Aircraft. It is based on the Grob G 120A training aircraft and has been developed for military and civil pilots trainin ...
Martin-Baker Mk.18
*
KAI KF-21 Boramae
The KAI KF-21 ''Boramae'' (formerly known as KF-X) is a South Korean lead fighter aircraft development program with the goal of producing an advanced multirole fighter for the South Korean and Indonesian air forces. The airframe is stealth ...
Operations
The Martin-Baker company uses its own airfield,
Chalgrove Airfield
Chalgrove Airfield is a former Second World War airfield in Oxfordshire, England. It is approximately north-northeast of Benson, Oxfordshire, Benson in the heart of South Oxfordshire between Henley and Oxford; about north-northwest of London. ...
, in Oxfordshire for operational testing of ejection seats. In 2016, ejection tests were carried out at
Cazaux Air Base
Cazaux Air Base (french: Base aérienne 120 Cazaux) is a French Air and Space Force (french: Armée de l'air et de l'espace) base. The base is located in the village of Cazaux, part of the town of La Teste-de-Buch, and is approximately southwe ...
; the company's Meteor aircraft testbeds were flown from Chalgrove to France for them.
Two Gloster Meteor T.7 aircraft, ''WL419'' and ''WA638'', remain in service with the company as flying testbeds. Another Meteor (''WA634''), used in early development of ejection seats, is retained at the
RAF Museum
The Royal Air Force Museum is a museum dedicated to the Royal Air Force in the United Kingdom. The museum is a non-departmental public body of the Ministry of Defence and is a registered charity.
The museum is split into two separate sites:
* R ...
at
RAF Cosford
Royal Air Force Cosford or RAF Cosford (formerly DCAE Cosford) is a Royal Air Force station in Cosford, Shropshire, Cosford, Shropshire, just to the northwest of Wolverhampton and next to Albrighton, Bridgnorth, Albrighton.
History
Origins
RA ...
.
Ejection Tie Club
Martin-Baker also sponsors an "Ejection Tie Club", producing a tie, patch, certificate, tie pin and membership card for those whose lives have been saved by a Martin-Baker ejection seat. The company also partnered with
Bremont
Bremont Watch Company is a luxury aviation-themed British watchmaker based in England. Annual production is approximately 10,000 pieces for an approximate annual revenue of £40 million.
History
Bremont was founded by brothers Nick and Giles En ...
to produce a limited-edition wristwatch for members of the club. The watch must be purchased privately, though Martin-Baker does subsidize its cost. , there are now over 6,000 registered members of the club since it was founded in 1957.
Red Arrows pilot incident
In 2011,
Red Arrows
The Red Arrows, officially known as the Royal Air Force Aerobatic Team, is the aerobatics display team of the Royal Air Force based at RAF Waddington. The team was formed in late 1964 as an all-RAF team, replacing a number of unofficial teams ...
pilot Flt. Lt.
Sean Cunningham was ejected from his
Hawk T1 jet on the ground at
RAF Scampton
Royal Air Force Scampton or RAF Scampton is a Royal Air Force station located adjacent to the A15 road near to the village of Scampton, Lincolnshire, and north-west of the city of Lincoln, England.
RAF Scampton stands on the site of a First ...
. The parachute failed to deploy and Cunningham was killed. On 22 January 2018, company director John Martin entered a guilty plea to breaching Section 3(1) of the Health and Safety at Work Act 1974 on behalf of Martin-Baker wherein he admitted that the company had been aware of a technical problem with the ejector seat since 1990, but failed to notify the RAF.
It transpired that both the MoD and the Health and Safety Executive had withheld evidence showing the company had regularly provided the necessary information to MoD since, at least, 1958. The primary evidence was in the form of an RAF training film. Had the instructions in the film been followed, Flt Lt Cunningham's parachute would have opened. It further emerged that MoD had instructed its staff not to implement this training, and re-issued this instruction after the accident. "The firm admitted the health and safety breach on the basis it had failed to provide a written warning to the RAF about over-tightening a bolt on the aircraft."
[BBC News, 23 Feb. 2019: https://www.bbc.com/news/uk-england-lincolnshire-43171049]
References
Notes
Bibliography
* Bowyer, Michael J.F. ''Interceptor Fighters for the Royal Air Force 1935-45''. Wellingborough, UK: Patrick Stephens Ltd., 1984. .
* Green, William, ed. "Mr. Martin's Memorable M.B.5." ''Air International'' Vol. 16, no. 2, February 1979.
* Green, William. ''War Planes of the Second World War: Fighters, Volume Two''. London, Macdonald & Co. (Publishers) Ltd., 1961.
* Green, William and Gordon Swanborough. ''WW2 Fact Files: RAF Fighters, Part 2''. London: Macdonald and Jane's Publishers Ltd., 1979. .
* Johnson, Brian and Terry Heffernan. ''A Most Secret Place: Boscombe Down, 1939–45.'' London: Jane's Publishing Company, 1982. .
"The Martin-Baker MB-V."''
Flight
Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be a ...
'', No. 1927, Volume XLVIII, 29 November 1945. p588-590
*
* Zuk, Bill. ''Janusz Zurakowski: Legends in the Sky.'' St. Catharine's, Ontario: Vanwell, 2004. .
* Ramsden J
"Martin-Baker: 50 years, 5,000 lives, 50,000 seats"''Flight International'', 26 May 1979 p1733-1735
External links
*
Electronic Library, see ''Propulsion Systems Contribution to Success of Aircrew Emergency Escape Systems''(PDF File, pay site)
a 1948 ''Flight'' article
a 1954 ''
Flight
Flight or flying is the process by which an object moves through a space without contacting any planetary surface, either within an atmosphere (i.e. air flight or aviation) or through the vacuum of outer space (i.e. spaceflight). This can be a ...
'' advertisement for Martin-Baker ejection seats
''VTOL''a 1966 ''Flight'' advertisement for Martin-Baker zero-speed zero altitude ('zero-zero') ejections seats
{{Authority control
Aircraft component manufacturers of the United Kingdom
British companies established in 1929
Companies based in Buckinghamshire
Denham, Buckinghamshire
Ejection seats
Science and technology in Buckinghamshire
Science and technology in Oxfordshire
Technology companies established in 1929
Family-owned companies of the United Kingdom
Privately held companies of the United Kingdom