Klaus Fuchs, Atomic Bomb Spy

Police photo, 1940

     Klaus Fuchs was born on 29th December, 1911, in Rüsselsheim, Germany, the third child in the family of two sons and two daughters. His father, renowned for his high Christian principles, was a pastor in the Lutheran church who joined the Quakers later in life and eventually became professor of theology at Leipzig University. Fuchs's grandmother, mother, and one sister committed suicide and his other sister was schizophrenic. 
     Fuchs studied physics and mathematics at the University of Leipzig and in 1931 he joined the German Communist Party. He fled the country when Hitler took power in 1933. He taught in Paris before moving to England where he studied Theoretical Physics. 
     Soon after his arrival he was the subject of a police inquiry because the German Counsul in Bristol named him as an extremist left-wing agitator. Not a great deal of credence was given to the allegation because such denunciations were fairly frequent and he was just another German who had fled the Nazis. After obtaining his PhD he took a position at Edinburgh University in the field of of quantum mechanics. After the outbreak of the War in 1939 he was interned with other German refugees in camps on the Isle of Man. 
     He was then transferred to a camp in Canada where he met Hans Kahle, who had fought with the International Brigades in the Spanish Civil War and Kahle gave Fuchs some addresses of left wing friends. 
     Fuchs was was released following the pleas of many distinguished scientists who claimed his skills were going to waste. In 1940, when it was clear that an atomic weapon was a serious possibility, Fuchs was recruited to do experimental and theoretical work back in England. Getting him a security clearance presented a problem at first, but it was eventually granted. 
     According to a document in the NKVD archives, Fuchs began spying for the Soviet Union in August 1941 when he was recruited by an exiled German Communist resident in Great Britain. Another file says that Fuchs passed material to their agent for the first time in September 1941. Fuch's Soviet controller was Ursula Beurton. 
     In 1943, Fuchs joined the Manhattan Project, the American atomic bomb program based in Los Alamos, New Mexico. However, Fuchs was based in the research unit in New York City and over the next few months he met five times with his Soviet contact and passed us a number of theoretical calculations on atomic fission and creation of the uranium bomb. His only financial reward consisted of occasional gifts. While in New York his courier reported that Fuchs was fully aware of what he was doing. 
     On March 28, 1944, Fuchs complained to his handler that his work was being curbed by the Americans who neglected cooperation and did not provide information and suggested that he might learn more by returning to England. Frustrated at the lack of success in the United States in October 1944 Major Pavel Fitin to build up a network of atomic spies. By that time the Soviets were pleased to hear that Fuchs had been transferred to Los Alamos. 
     In 1946 Klaus Fuchs returned to England, where he was appointed as head of the theoretical physics division at the newly created British Nuclear Research Centre at Harwell. At that time, Fuchs approached members of the Communist Party of Great Britain in order to get back in contact with the NKVD. He finally met with NKVD agents in July of 1947 and explained the principle of the hydrogen bomb on which Enrico Fermi and Edward Teller were working on at the University of Chicago. By this time Fuchs’ father was his dependent and his brother had tuberculosis and so he was given £200. He returned £100 on the grounds that he could not explain the sudden appearance of £200. 
     In March 1948 Soviet agents were ordered to keep clear of Fuchs because the Daily Express had reported that British counter-intelligence were investigating three unnamed scientists who were suspected of being members of the Communist Party of Great Britain. Also, one of Fuchs' former contacts had been interviewed by the FBI. 
     In September 1949, MI5 was sent documents that suggested that Fuchs was a Soviet spy. His telephones were tapped and his correspondence intercepted at both his home and office. Concealed microphones were installed in his home and he was tailed by surveillance teams, who reported that he was difficult to follow. Although they discovered he was having an affair with the wife of his manager, the investigation failed to produce any evidence of espionage. 
     In January 1950, the head of MI5, wrote to Fuchs's boss pointing out that they had had Fuchs' activities under intensive investigation for more than four months and that his continued employment was a constant threat to security.
     Fuchs was interviewed by MI5, but denied any involvement in espionage and they did not have enough evidence to have him arrested and charged with spying. Fuchs was, however, under considerable mental stress, but told investigator that he could never be persuaded to talk to them. 
     Nevertheless, after having lunch with an investigator, Fuchs decided it would be in his best interests to answer questions. Fuchs explained the reason was that he had complete confidence in Russian policy and believed that the Western Allies deliberately allowed Russia and Germany to fight each other. Fuchs didn’t realize that, but for his confession, there would have been no case against him, and what they did have was unusable in court. 
     A few days later J. Edgar Hoover informed President Harry Truman that "we have just gotten word from England that we have gotten a full confession from one of the top scientists, who worked over here, that he gave the complete know-how of the atom bomb to the Russians." 

     Fuchs was found guilty in March 1950 of four counts of breaking the Official Secrets Act. After a trial lasting less than 90 minutes, he entenced him to fourteen years' imprisonment, the maximum for espionage, because the Soviet Union was classed as an ally at the time. Hoover reported that "Fuchs said he would estimate that the information furnished by him speeded up by several years the production of an atom bomb by Russia." 
     Fuchs was released on June 23, 1959 after serving nine years and four months and immediately joined his father and one of his nephews in what had become the German Democratic Republic, that is, the Communist East Germany. He was appointed deputy director of the Institute for Nuclear Research near Dresden. Fuchs married a friend from his student days and died on January 28, 1988. 

You can take a look at the FBI files on Fuchs on their records vault HERE. 
Spies Who Spilled Atomic Bomb Secrets 
Books on Fuchs at Amazon