Klaus Fuchs was born on 29th December, 1911, in Russelsheim, Germany. He studied physics and mathematics at the University of Leipzig. A member of the Germany Communist Party, Fuchs was forced to flee the country after the Nazis gained power in 1933.
Fuchs moved to Scotland where he continued he studies. On the outbreak of the Second World War, Fuchs was briefly interned but was released when it was discovered that his knowledge of physics would be useful to the British government. He worked at Birmingham University under Rudolf Peierls, another German refugee physicist in England. In 1943 Fuchs was sent to the United States where he worked at Los Alamos on developing the atom bomb.
After the war Fuchs returned to England where he became head of the physics department of the British nuclear research centre at Harwell.
On 5th September 1945, Igor Gouzenko, a KGB intelligence officer based in Canada, defected to the West claiming he had evidence of an Soviet spy ring based in Britain. Gouzenko provided evidence that led to the arrest of 22 local agents and 15 Soviet spies in Canada. Some of this information from Gouzenko resulted in Fuchs being interviewed by MI5.
Fuchs denied any involvement in espionage and the intelligence services did not have enough evidence to have him arrested and charged with spying. However, after repeated interviews with Jim Skardon he eventually confessed on 23rd January 1950 to passing information to the Soviet Union . Six weeks later Fuchs was sentenced to 14 years in prison.
In 1950 the FBI arrested Harry Gold, who confessed to helping Fuchs in his espionage activities in the United States. As a result of Gold's testimony, other spies, including David Greenglass, Ethel Rosenberg and Julius Rosenberg were arrested and convicted.
After his release on 24th June 1959, he went to East Germany where he became deputy director of the Central Institute for Nuclear Research in Rossendorf. Klaus Fuchs died on 28th January, 1988.
In 1940, when it was clear that an atomic weapon was a serious possibility, and that it was urgent to do experimental and theoretical work, I wanted someone to help me with the theoretical side. Most competent theoreticians were already doing something important, and when I heard that Fuchs, whom I knew and respected as a physicist from his work at Bristol, was back in the UK, temporarily in Edinburgh, it seemed a good idea to try to get him to come to Birmingham. There was at first some difficulty about security clearance, and I was told I could not tell him what it was all about.... I explained that in the kind of work that had to be done he could be of no use to me unless he knew exactly what one was trying to do, and that there was no half-way house. In the end he was cleared.
We have had Fuchs' activities under intensive investigation for more than four months. Since it has been generally agreed that Fuchs' continued employment is a constant threat to security and since our elaborate investigation has produced no dividends, I should be grateful if you would be kind enough to arrange for Fuchs' departure from Harwell as soon as is decently possible.
He was obviously under considerable mental stress. I suggested that he should unburden his mind and clear his conscience by telling me the full story. He (Fuchs) said: 'I will never be persuaded by you to talk." At this stage we went to lunch. During the meal he seemed to be resolving the matter and to be considerably abstracted... He suggested that we should hurry back to his house. On arrival he said that he had decided it would be in his best interests to answer my questions. I then put certain questions to him and in reply he told me that he was engaged in espionage from mid 1942 until about a year ago. He said there was a continuous passing of information relating to atomic energy at irregular but frequent meetings.
I was a student in Germany when Hitler came to power. I joined the Communist Party because I felt I had to be in some organization. I was in the underground until I left Germany. The Communist Party said that I must finish my studies because after the revolution in Germany people would be required with technical knowledge to take part in the building of the Communist Germany. I went first to France and then to England, where I studied and at the same time I tried to make a serious study of the bases of Marxist philosophy.
I had my doubts for the first time (August, 1939) on acts of foreign policies of Russia; the Russo-German pact was difficult to understand, but in the end I did accept that Russia had done it to gain time, that during the time she was expanding her own influence in the Balkans against the influence of Germany.
Shortly after my release (from detention as an enemy alien) I was asked to help Professor Peierls in Birmingham, on some war work. When I learned the purpose of the work I decided to inform Russia and I established contact through another member of the Communist Party. Since that time I have had continuous contact with the persons who were completely unknown to me, except that I knew they would hand whatever information I gave them to the Russian authorities. At that time I had complete confidence in Russian policy and I believed that the Western Allies deliberately allowed Russia and Germany to fight each other to the death. I had therefore, no hesitation in giving all the information I had, even though occasionally I tried to concentrate mainly on giving information about the results of my own work.
There is nobody I know by name who is concerned with collecting information for the Russian authorities. There are people whom I know by sight whom I trusted with my life.
When I learnt of the purpose of the work, I decided to inform Russia, and I established contact with another member of the Communist Party. Since that time I have had continuous contact with persons who were completely unknown to me, except that I knew they would give whatever information they had to the Soviet authorities. At this time I had complete confidence in Russian policy and believed that the Western Allies deliberately allowed Germany and Russia to fight each other to death.