The successful test of an atomic bomb in Operation Hurricane in October 1952 represented an extraordinary scientific and technological achievement . Britain became the world 's third nuclear power , reaffirming the country 's status as a great power , but hopes that the United States would be sufficiently impressed to restore the Special Relationship were soon dashed . In November 1952 , the United States conducted Ivy Mike , the first successful test of a true thermonuclear device or hydrogen bomb . Britain was therefore still several years behind in nuclear weapons technology . The Defence Policy Committee , chaired by Churchill and consisting of the senior Cabinet members , considered the political and strategic implications in June 1954 , and concluded that " we must maintain and strengthen our position as a world power so that Her Majesty 's Government can exercise a powerful influence in the counsels of the world . " In July 1954 , Cabinet agreed to proceed with the development of thermonuclear weapons
Ivy Mike
Ivy Mike
Operation Grapple