Ernest Holloway Oldham

Ernest Holloway Oldham (September 10, 1894 – September 29, 1933) was a cipher clerk in the British Foreign Office who spied for the Soviet Union between 1929 and his death in 1933, in return for money. His job gave him access to highly sensitive communications between Britain and her foreign embassies, and the material he passed to his handler Dmitri Bystrolyotov was highly regarded in Moscow. He had no apparent ideological interest in helping the Soviet Union (unlike the more famous Cambridge spies), but was driven by the large amounts of money paid to him to betray his country. By 1933, the pressures of his activities had led to his sacking from the Foreign Office, alcoholism, domestic violence and ultimately suicide.

Despite hints to there being a spy within the Foreign Office by Soviet defectors Grigory Besedovsky (in October 1929) and Georges Agabekov (in June 1930), Oldham's espionage was only partly suspected by his employers during the last months of Oldham's life, when MI5 began their investigation and surveillance. His activities were uncovered in 1940 when Oldham was identified by the Soviet defector Walter Krivitsky during his interrogations with MI5.