John Cairncross

John Cairncross (25 July, 1913 – 8 October, 1995) was a British intelligence officer during World War II who passed secrets to the Soviet Union during the war.  He was alleged to be the fifth member of the Cambridge Five.

The brother of economist Sir Alexander Kirkland Cairncross (a.k.a. Alec Cairncross) and the uncle of journalist Frances Cairncross, Cairncross was born in Lesmahagow, Scotland, and educated at the University of Glasgow and Trinity College, Cambridge, where he studied modern languages.

After graduating, he worked in the Foreign Office.  In 1937 he joined the Communist party.  In 1942 he worked on ciphers at Bletchley Park and MI6.  During this time, he passed documents through secret channels to the Soviet Union.  While at Bletchley Park, he supplied the Soviets with advance intelligence from ULTRA about what became the critical Battle of Kursk.  The information he supplied enabled the Soviets to keep their ciphers one step ahead of British Intelligence, and also helped win the war against Hitler on the Eastern Front.

Cairncross admitted to spying in 1951 after MI5 found incriminating papers in his possession.  Some believe that the information he supplied about the Western atomic weapons programmes kick-started the Soviet nuclear programme.  He was never prosecuted, however, which later led to charges that the government engaged in a conspiracy to cover up his role.  Indeed, the identity of the infamous “fifth man” in the Cambridge Five remained a mystery until 1990, when KGB defector  Oleg Gordievsky fingered Cairncross.

Between 1941 and 1945, Cairncross supplied the Soviets with 5,832 documents, according to Russian archives.

Cairncross denied passing any information harmful to Britain, including atomic secrets.  He also denied that he was the “Fifth Man” in the Cambridge spy ring. In his autobiography, he claimed his motivation was to assist the Soviet Union in defeating Nazi Germany.

After his confession, Cairncross moved to Rome, where he worked for the United Nations Food and Agricultural Organization.  He worked as economic papers translator for Research Office of Banca Nazionale del Lavoro, Banca d’Italia and IMI.  In the BNL, a young economist engaged with international scenarios analysis (Iraq – Iran War, oil’s strategic routes in Middle East and Far East) revealed a strong and unusual interest by Cairncross about the Bank’s role for that area.  He retired to the south of France. John Cairncross died in 1995, aged 82.