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
Atomic Heritage Foundation local communities, and other organizations to urge Congress to establish a Manhattan Project National Historical Park. In March 2013, Senators Maria Cantwell and Lamar Alexander introduced S. 507 to create a park, and Representatives Doc Hastings, Ben Ray Lujan, and Chuck Fleischmann introduced a companion bill in the House, H.R. 1208. The Los Alamos, V-Site was the site of assembly for the Trinity device, the first atomic weapon ever detonated. In October 2006, the AHF co-hosted several days of events to commemorate the successful restoration of the High Bay building. The Atomic Heritage Foundation has created several museum exhibits. They