CATCHING THE RED FOX

On the surface, Klaus Fuchs was a diligent young scientist, enthusiastically helping Britain and the US develop powerful new weapons during World War II. But, as Roger Hermiston reveals, his true loyalties lay elsewhere

- ROGER HERMISTON

Early in April 1941 at a party in Flat No 6 in the gleaming, white, ultra-modernist Isokon Building (otherwise known as the Lawn Road Flats) in London's leafy Hampstead, there was an encounter between two men that would affect the course of the 20th century. It could also, if there had ever been tangible evidence it had taken place, have meant the hangman's noose for one of the participants.

The younger of the pair was tall, thin, with round spectacles and a high forehead, and wore a serious expression on his face. The other, with sharp chiselled features and rather feminine eyes, appeared notably more relaxed despite a stiff, military bearing.

The individuals concerned were German-born Klaus Emil Julius Fuchs, a brilliant 29-year-old theoretical physicist just released from an internment camp in Canada, and 40-year-old Simon Davidovich Kremer, a former tank commander, and now officially secretary to the military attaché at the Soviet Embassy in London.

They had one thing in common - they were both committed communists with the interests of Stalin's Soviet Union at heart. This was fine for Kremer, whose day job was official business for the Kremlin - although by night, as it were, he was a spy, working for the Soviet 'Fourth Department' of military intelligence (the GRU).

Fuchs, however, was doing everything he could to conceal his ideological beliefs from his British hosts. It was bad enough - but not surprising, given his nationality and the suspicions of wartime that he had just spent six months in camps in the Isle of Man and Canada. But to have had his past Communist Party associations revealed would have put an end to his application for British citizenship and his hopes of an academic career in the country.