British hydrogen bomb programme Atomic Energy Act of 1946 (also known as the McMahon Act) ended technical cooperation. Fearing a resurgence of American isolationism, and the loss of Britain's great power status, the British government resumed its own development effort, which was codenamed "High Explosive Research". The successful nuclear test of a British 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 nuclear Special Relationship were soon dashed. In November
British nuclear testing in the United States which led to the agreement on the use of the Maralinga test site in August 1954. The first of the British nuclear tests at Maralinga was held in September 1956. While British atomic bomb development represented an extraordinary scientific and technological achievement, hopes that the United States would be sufficiently impressed to restore the nuclear Special Relationship were 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