1958 US–UK Mutual Defence Agreement as an atomic spy, caused the proposal to be dropped. The June 1951 defection of Donald Maclean, who had served as a British member of the Combined Policy Committee from January 1947 to August 1948, reinforced the Americans' distrust of British security arrangements. The first British atomic bomb was successfully tested in Operation Hurricane on 3 October 1952, but although it was more advanced than the American bombs of 1946, Britain was still several years behind in nuclear weapons technology. The United States conducted Ivy Mike, the first nuclear test of a true thermonuclear device (also known as a hydrogen
History of nuclear weapons the United Kingdom also had an atomic bomb and a successful test took place on 3 October 1952. At first these were free-fall bombs, intended for use by the V Force of jet bombers. A Vickers Valiant dropped the first UK nuclear weapon on 11 October 1956 at Maralinga, South Australia. Later came a missile, Blue Steel, intended for carriage by the V Force bombers, and then the Blue Streak medium-range ballistic missile (later canceled). Anglo-American cooperation on nuclear weapons was restored by the 1958 US-UK Mutual Defence Agreement. As a result of this and the Polaris Sales Agreement, the