The United Kingdom became the third country to develop and, in 1952, test nuclear weapons. The UK is one of nine nuclear-armed states, and one of five recognized by the Treaty on the Non-Proliferation
HMS Victorious, one of four nuclear-armed ballistic missile submarines of the Trident programme
James Chadwick (left), the head of the British Mission, confers with Major General Leslie R. Groves, Jr. (right), the director of the Manhattan Project
President Harry Truman and the prime ministers Clement Attlee and Mackenzie King boarding USS Sequoia for discussions about nuclear weapons, November 1945
William Penney, Chief Superintendent Armament Research, was in charge of atomic bomb development.
Letters of last resort
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The letters of last resort are four identically worded handwritten letters from the prime minister of the United Kingdom to the commanding officers of the four British nuclear-powered ballistic missil
Nuclear weapons of the United Kingdom
…unreachable a designated deputy, while it is possible the Chief of the Defence Staff holds a veto. In the event of a decapitation strike, handwritten letters of last resort from the Prime Minister are used to instruct submarine crews. UK nuclear weapons have no permissive action links or corresponding launch codes, thus…
HMS Vigilant, one of four Vanguard-class submarines comprising the UK's nuclear deterrent.