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
Operation Sandstone delivered to San Pedro, California, and loaded on the weapon assembly ship USS "Curtiss", in February 1948, but the Atomic Energy Commission only gave permission for the expenditure of three cores in the tests. The naval forces were organized as Task Group 7.3. It consisted of: Source: Berkhouse "et al", "Operation Sandstone", p. 40 In September 1947, Hull, Russell, who was designated test director on October 14, and Joint Task Force 7's scientific director, Darol K. Froman from the Los Alamos Laboratories, set out with a group of scientists and military officers to examine various proposed test sites in the