January 24 – Cold War: Klaus Fuchs, German émigré and physicist, walks into London's War Office and confesses to being a Soviet spy: for 7 years, he passed top secret data on U.S. and British nuclear weapons research to the Soviet Union; formally charged February 2.
Klaus Fuchs was a German-British theoretical physicist and atomic spy who in 1950 was convicted of supplying information from the American, British and Canadian atomic bomb research (the Manhattan Project) to the USSR during and shortly after World War II. While at the Los Alamos National Laboratory, Fuchs was responsible for many significant theoretical calculations relating to the first fission weapons and later, the early models of the hydrogen bomb, the first fusion weapon.
Espionage information procured by Klaus Fuchs and Theodore Hall, and to a lesser extent by David Greenglass, led to the first Soviet device, "RDS–1", closely resembling Fat Man, even in its external shape.
Atomic Spies-- spies who infiltrated the ranks of the Manhattan Project and spilled the secrecy within to the Soviet Union. Some include: Klaus Fuchs, Harry Gold, David Greenglass, Ethel and Julius Rosenberg.