Fuchs, Klaus-Emil

(1910–1988)

   A gifted physicist, Fuchs fled to London from Nazi Germany in the early 1930s. While he was involved in the early British nuclear weapons program codenamed “Tube Alloy,” he volunteered to work for Soviet intelligence. In Great Britain, Fuchs originally was run by a GRU illegal, but his case was transferred to the NKVD after Fuchs moved to the United States to work at Los Alamos. Fuchs was probably the most important of several Soviet penetrations of the nuclear weapons program codenamed Enormoz. He was run by a series of illegals. His NKVD code names were “Rest” and “Charles.”

   On his return to Britain after World War II, Fuchs maintained contact with Soviet intelligence, passing on information about the British nuclear weapons program for four years. Under suspicion, Fuchs was arrested and confessed to a British counterintelligence interrogator in 1950. He was tried and sentenced to 14 years imprisonment. Released after nine years, Fuchs returned to East Germany, where he worked as a nuclear physicist. He was a member of the Communist Party Central Committee, and he died in 1988, a year before the collapse of the system he served. Of the spies within the American nuclear program, Fuchs and Ted Hall were probably the most important sources of information about both the progress of the Anglo-American project and solutions to the problems facing American and British bomb makers. According to nuclear physicist and Nobel Prize laureate Andrei Sakharov, Fuchs provided the Soviet nuclear program with critical intelligence gathered from Los Alamos and later from London. He also provided the first information Moscow received about the “Super” H-Bomb.