Rüsselsheim (Hesse) on 29 December 1911, the son of a Quaker min-
ister. As a student of physics at the University of Leipzig in 1930, he
joined the Sozialistische Demokratische Partei but abandoned it two
years later while at the University of Kiel, becoming a member of
the Kommunistische Partei Deutschlands (KPD). In 1933, Fuchs was
branded a political criminal by the Nazis and, obeying the orders of
the KPD, immigrated to England to complete his studies. He received
a doctorate from the University of Bristol in 1936, and in spite of
his communist affiliation, the British Home Office granted him an
unlimited residence permit. Although interned briefly on the Isle of
Man and in Canada after the outbreak of World War II, Fuchs was
released in 1941 because of his potential value as a nuclear physicist.
Impressed by his scientific papers, Rudolf Peierls invited him to join
his laboratory in Birmingham, which was involved in the top-secret
project of developing an atomic bomb to be used in the war against
Adolf Hitler (code name tube alloys). Upon the recommendation
of Tube Alloys, Fuchs became a naturalized citizen in June 1942,
declaring that he would “bear true allegiance” to the British crown
“according to law.”
Fuchs, however, was anxious to lend active support to the Soviet
Union, and in fall 1941 he was advised by his friend and fellow com-
munist Jürgen Kuczynski to contact the Soviet embassy in London.
Fuchs was assigned a control officer from the GRU (Soviet military
intelligence), Simon Kremer, to be replaced the following year by
Ursula Kuczynski, Jürgen’s sister. All the scientific research in-
formation at his disposal was relayed to Moscow. With his appoint-
ment as a member of the British mission to the Manhattan Project in
December 1943, Fuchs’s access to nuclear secrets increased signifi-
cantly. Fuchs’s NKGB controller, known to him as Raymond, was
Harry Gold, a biochemistry technician born in Switzerland of Russian
parents. By August 1944, Fuchs (code names rest and charles) had
moved to the bomb design and assembly laboratory at Los Alamos,
New Mexico, unaware, however, that several other scientists there
likewise maintained undercover links to the Soviet Union. While the
precise contents of Fuchs’s reports cannot be determined, he did pos-
sess wide knowledge, especially regarding the theory and design of
a gaseous diffusion plant and the implosion method for assembling
an atomic bomb.
FUCHS, KLAUS • 121