The History of the UK Nuclear Weapons Programme

This timeline has been prepared by Nuclear Information Service to mark the sixtieth anniversary of the first atomic test by the United Kingdom on 3 October 1952. It outlines key events in the development of the UK's nuclear weapons programme from the decision to begin research into atomic weapons during World War II to the current debate on whether to replace the UK's Trident nuclear weapons.

;xNLx;;xNLx;For more information on current developments in the UK's nuclear weapons programme please visit;xNLx;;xNLx;;xNLx;For further details about the history of the UK nuclear weapons programme the following reading is recommended:;xNLx;;xNLx;‘Britain and the H-Bomb’ by Lorna Arnold with Katherine Pyne (Palgrave 2001). ;xNLx;'Cabinets and the Bomb' by Peter Hennessy (Oxford University Press 2007);xNLx;'U.S.-UK Nuclear Co-operation after 50 Years' edited by Jenifer Mackby and Paul Cornish (CSIS Press, 2008);xNLx;;xNLx;;xNLx;Every effort has been made to ensure the accuracy of information in the timeline and trace copyright owners for images used in the timeline. If you would like to suggest any corrections or provide further information on copyright holders we would be very pleased to hear from you. Please contact us at office (at)

1940-01-01 00:00:00

Britain begins work on the atom bomb

Britain begins work on developing an atomic bomb - the first nation in the world to do so. The 'Maud Committee' is established to consider how to harness nuclear energy for weapons use and how to separate uranium 235 from natural uranium for use in a weapon.

1941-11-16 18:14:02

Directorate of Tube Alloys

The clandestine Directorate of Tube Alloys is set up to continue the UK's research into development of an atomic bomb.

1942-09-12 00:00:00

The Manhattan Project

The Manhattan Project on nuclear weapons research and development produces the world's first atomic bomb in the USA. The UK joins the project in 1943, contributing scientists and expertise from the Tube Alloys project.

1943-08-19 00:00:00

Quebec Agreement

Britain, Canada, and the USA sign the Quebec Agreement “to bring the Tube Alloys [i.e. the Atomic Bomb] project to fruition at the earliest moment”. Work continues under the auspices of the USA's Manhattan Project.

1945-07-16 04:45:35

The Trinity Test

The US explodes the world’s first atomic bomb in the 'Trinity' nuclear test at Alamogordo, New Mexico.

1945-08-06 04:45:35

Hiroshima and Nagasaki

The United States drops atomic bombs on the Japanese cities of Hiroshima and Nagasaki.

1946-01-01 00:00:00

Atomic Energy Research Establishment

The Atomic Energy Research Establishment (AERE) is established at Harwell as the main centre for military and civilian atomic energy research and development in Britain.

1946-08-01 04:45:35

McMahon Act

The USA passes the Atomic Energy Act 1946 - known as the 'McMahon Act’ after the author of the Act, Senator Brien McMahon - into law. The Act forbids the sharing of US nuclear technology with other nations, putting a halt to all collaboration with Britain on nuclear weapons.

1947-01-10 01:43:57

Work restarts on the British atomic bomb project

Work officially restarts on the British atomic bomb project following World War 2. The decision is taken at a secret Cabinet subcommittee set up by Labour Prime Minister Clement Attlee. Ernest Bevin, then Foreign Secretary, argues that Britain must develop the bomb in order to maintain its status with the USA, allegedly saying: 'We’ve got to have this thing over here, whatever it costs. We’ve got to have the bloody Union Jack on top of it.'

1947-12-16 18:41:14

Fort Halstead

Fort Halstead in Kent becomes the base for the High Explosives Research team, headed by Chief Superintendent Armaments Research William Penney, which will eventually design Britain’s first atomic bomb.

1949-04-04 04:45:35

The North Atlantic Treaty

The North Atlantic Treaty is signed, creating the North Atlantic Treaty Organisation (NATO). Britain is one of the twelve original signatories.

1949-08-29 04:45:35

The Soviet Union develops the atom bomb

The Soviet Union conducts 'First Lightening', its first atomic test explosion, making it the second nation after the USA to become a nuclear-weapon state.

1950-04-01 04:45:35

AWRE Aldermaston

The Atomic Weapons Research Establishment (AWRE) opens at the former RAF Aldermaston airfield in Berkshire as the new headquarters of the British atomic weapon programme under the directorship of William Penney

1952-10-03 04:45:35

First British atom bomb test

Operation Hurricane, the first British atomic bomb test, takes place in the Montebello Islands off the north west coast of Australia.

1955-01-01 04:45:35

Britain's atom bomb enters service

The first of Britain's V-bomber aircraft, the Vickers Valiant, enters service with 138 Squadron at RAF Gaydon, initially armed with atomic weapons supplied by the USA and then with Blue Danube bombs - the first operational British nuclear weapon

1955-05-14 04:45:35

Warsaw Pact signed

The Warsaw Treaty Organisation (Warsaw Pact) is formed between the Soviet Union and several Eastern European nations.

1955-12-01 04:45:35

Blue Streak

Development of the Blue Streak intermediate range ballistic missile commences as a delivery system to replace the V-bombers when they become obsolete in the mid 1960s.

1956-10-11 04:45:35

First UK air drop test

A Valiant bomber drops a live Blue Danube nuclear bomb in the first UK air drop test explosion while flying over the Maralinga test range in Australia.

1957-05-15 04:45:35

First British hydrogen bomb test

Britain's first hydrogen bomb is tested at Malden Island in the Pacific Ocean as part of Operation Grapple – the programme to develop British thermonuclear weapons. The first Grapple test, Green Granite, exploded with a yield far below its designers' intentions, but subsequent tests met the design objectives.

1957-10-10 04:45:35

The Windscale fire

The Windscale fire - the worst nuclear accident in Britain's history - breaks out in reactors producing plutonium for the UK nuclear weapons programme at the Windscale nuclear plant in Cumbria.

1958-02-17 04:45:35

Campaign for Nuclear Disarmament formed

The Campaign for Nuclear Disarmament (CND) is formed to campaign for the global elimination of nuclear weapons.

1958-04-04 04:45:35

The first Aldermaston march

The first Aldermaston march takes place over the Easter weekend, organised by the Direct Action Committee and supported by the Campaign for Nuclear Disarmament. Several thousand people march from Trafalgar Square in London to AWRE Aldermaston to protest about the UK's H-bomb programme.

1958-07-03 04:45:35

US - UK Mutual Defense Agreement

The US-UK Mutual Defense Agreement on nuclear co-operation is signed. The agreement allows co-operation on the design and testing of nuclear weapons, nuclear weapons manufacturing, and nuclear reactor technology, allowing the UK to benefit from the more comprehensive US nuclear weapons programme and giving the US access to the UK's better theoretical modelling and conventional explosives technology.

1958-09-23 04:45:35

Last British nuclear test in the Pacific

The last nuclear test in the Operation Grapple series takes place off Christmas Island. All further UK tests are conducted jointly with the USA and most subsequent UK nuclear weapons were close copies of American designs.

1960-02-01 04:45:35

Blue Streak cancelled

The Cabinet decides to cancel the Blue Streak missile project because of escalating costs and vulnerability of the system to a pre-emptive attack.

1960-03-21 04:45:35


President Eisenhower agrees to sell the US Skybolt missile to the UK for use with the V-bomber force as a substitute for the cancelled Blue Streak programme.

1962-03-01 04:45:35

First joint US-UK nuclear test

The 'Pampas' nuclear test takes place as part of Operation Nougat - the first of a series of joint US-UK nuclear weapon tests held under the terms of the 1958 Mutual Defence Agreement at the Nevada Test Site.

1962-10-15 00:00:00

The Cuban Missile Crisis

The Cuban Missile Crisis confrontation between the USA and the Soviet Union over the basing of Soviet nuclear weapons in Cuba brings the world close to nuclear war. Britain's nuclear V-bomber force is placed at the highest level of alert as the crisis reaches its peak.

1962-12-22 04:45:35

Nassau Agreement

The sudden cancellation of the Skybolt project by President Kennedy causes a crisis for the UK's nuclear weapons programme. The Nassau Summit between Prime Minister Macmillan and President Kennedy results in the Nassau Agreement under which the US agrees to sell the Polaris submarine launched ballistic missile system to the UK as a substitute for Skybolt, in return for use of the Holy Loch as a base for US nuclear submarines.

1963-04-06 04:45:35

Polaris Sales Agreement

The Polaris Sales Agreement is signed between the USA and the UK, under which the USA agrees to provide the UK with Polaris missiles, launch tubes, and fire control system for the missiles. The UK is to develop its own nuclear warhead and submarines.

1964-02-26 04:45:35

Construction of HMS Resolution begins

Construction work begins on HMS Resolution, the first of the Royal Navy's four Resolution-class Polaris ballistic missile submarines, at the Vickers Armstrong shipyard in Barrow-in-Furness

1965-04-01 00:00:00

TSR2 aircraft project cancelled

Harold Wilson's Cabinet decides to cancel plans to build the TSR2 aircraft in the light of the high costs of the project. TSR2 was intended to be a British designed and built strike and reconnaissance aircraft with a tactical nuclear weapon capability.

1966-09-01 04:45:35

WE177 tactical nuclear bomb deployed

The air-launched WE177 tactical nuclear bomb is first deployed. It will eventually become the longest serving UK nuclear weapon.

1968-06-15 04:45:35

Polaris enters service

HMS Resolution begins the first operational patrol, armed with Polaris missiles carrying UK-built warheads based on the US W47 warhead design. The UK begins a policy of continuous-at-sea-deterrence, with at least one submarine carrying nuclear weapons at sea at all times.

1968-07-01 04:45:35

UK signs the Non-Proliferation Treaty

The UK signs the Nuclear Non-Proliferation Treaty (NPT) as a depository state with Russia and the USA.

1970-03-05 00:00:00

Non-Proliferation Treaty enters into force

The Nuclear Non-Proliferation Treaty (NPT) enters into force for an initial period of 25 years.

1974-02-01 04:45:35

Work begins on the Chevaline programme

Prime Minister Harold Wilson gives the go ahead in secret for work to begin on Chevaline, a programme to develop a new 'front end' system for Polaris missiles, with new hardened warheads, hardened re-entry vehicles, and penetration aids, following a series of studies which commenced in the late 1960s into how Polaris could be upgraded to overcome Soviet anti-ballistic missile defences.

1978-08-17 10:46:06

Pochin Inquiry into safety at AWRE

Sir Edward Pochin, a member of the National Radiological Protection Board, is appointed by the government to inquire into health and safety at the Atomic Weapons Research Establishment after production of fissile components at the Establishment is halted when 12 workers are found to have accumulated plutonium in their lungs. Pochin's report makes 73 recommendations and leads to a major overhaul of safety procedures at the Establishment.

1978-12-01 04:45:35

Duff-Mason report

Ministers receive the 'Duff-Mason report' on the future of the UK's nuclear weapons. The report, summarising the findings of working parties led by Sir Anthony Duff from the Foreign and Commonwealth Office and Professor Sir Ronald Mason from the Ministry of Defence, recommends that the Polaris system should be replaced with the submarine launched Trident C4 system, to be purchased from the USA.

1979-01-01 04:45:35

US agrees to sell Trident to the UK

At a meeting in Guadeloupe, US President Jimmy Carter indicates to Prime Minister James Callaghan that he is prepared to sell Trident to the UK.

1980-01-24 04:45:35

Chevaline programme revealed

The existence of the Chevaline programme is disclosed for the first time by Conservative Defence Secretary Francis Pym during a debate in Parliament. The project's cost had risen from an initial estimate of £175 million to a total cost of over £1 billion, resulting in a highly critical report published subsequently by the House of Commons Public Accounts Committee.

1980-07-10 04:45:35

Trident C4 deal

Prime Minister Margaret Thatcher agrees a deal with US President Jimmy Carter to buy the Trident C4 nuclear weapons system from the USA.

1982-03-11 04:45:35

Trident D5 sale agreed

President Ronald Reagan formally agrees to sell the Thatcher government the more powerful Trident II D5 system from the USA, instead of Trident C4, under an extension of the Polaris Sales Agreement.

1983-03-01 04:45:35

Defence Secretariat 19

Defence Secretary Michael Heseltine sets up a secret unit within the Ministry of Defence called Defence Secretariat 19 to combat growing public support for nuclear disarmament.

1983-10-22 04:45:35

CND's largest ever demonstration

250,000 people protest against nuclear weapons in London at a demonstration organised by the Campaign for Nuclear Disarmament - CND's largest ever demonstration.

1983-11-02 00:00:00

Able Archer 83

The 'Able Archer 83' military exercise by NATO forces causes the Soviet Union to believe it is under attack. A nuclear conflict is narrowly averted.

1986-09-03 04:45:35

Construction of HMS Vanguard begins

Construction work starts on HMS Vanguard, the first of the Vanguard class of Royal Navy nuclear ballistic missile submarines which will carry the Trident D5 missile system.

1987-09-01 04:45:35

Atomic Weapons Establishment is formed

The Atomic Weapons Research Establishment (AWRE) is merged with Royal Ordnance Factories at Burghfield, Cardiff, and Foulness to form the Atomic Weapons Establishment (AWE). The new establishment is responsible for all aspects of the design, manufacture, and support of Britain's nuclear warheads.

1989-11-09 00:00:00

Berlin Wall falls

The East German government announces that its citizens can visit West Germany, leading to the fall of the Berlin Wall and the end of the Cold War.

1991-11-26 04:45:35

Last US-UK nuclear test

'Bristol', the last joint US-UK nuclear test prior to President George H. W. Bush's moratorium on underground nuclear testing, takes place at the Nevada Test Site. In total, the UK conducted a total of 48 nuclear weapon tests, 28 of which were at Nevada.

The History of the UK Nuclear Weapons Programme

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