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
Bulletin of the Atomic Scientists as a not-for-profit 501(c)(3) organization to serve as the parent organization and fundraising mechanism of the "Bulletin". In 2003, the Board of Directors voted to change the foundation's name to Bulletin of the Atomic Scientists. The "Bulletin of the Atomic Scientists" began as an emergency action undertaken by scientists who saw urgent need for an immediate educational program about atomic weapons. The intention was to educate fellow scientists about the relationship between their world of science and the world of national and international politics. A second was to help the American people understand what nuclear energy and its possible applications