During the early part of the Second World War , Britain had a nuclear weapons project , codenamed Tube Alloys . At the Quebec Conference in August 1943 , the Prime Minister of the United Kingdom , Winston Churchill and the President of the United States , Franklin Roosevelt , signed the Quebec Agreement , which merged Tube Alloys with the American Manhattan Project to create a combined British , American and Canadian project . The British government trusted that the United States would continue to share nuclear technology , which it regarded as a joint discovery , after the war , but the United States Atomic Energy Act of 1946 ( McMahon Act ) ended technical cooperation . Its control of " restricted data " prevented the United States ' allies from receiving information related to nuclear weapons . Fearing a resurgence of United States isolationism , and Britain losing its great power status , the British government restarted its own development effort , which was codenamed High Explosive Research . The first British atomic bomb was successfully detonated off the Monte Bello Islands in Operation Hurricane on 3 October 1952 , and the first production model atomic bomb was delivered to the Royal Air Force ( RAF ) in November 1953
Operation Hurricane
Operation Hurricane
Project Emily