Sidney Reilly (c. 1873-1925), born Sigmund Rosenblum in the Russian Empire, was an agent of the British Secret Intelligence Service whose life was later mythologized as “Ace of Spies.” In 1918 he was in Soviet Russia working against the Bolshevik government and was implicated in the so-called Lockhart or Ambassadors’ plot. He escaped, and in December 1918 a Soviet revolutionary tribunal sentenced him to death in absentia.

Reilly remained active in anti-Bolshevik émigré circles and was associated with Boris Savinkov. In September 1925 he was lured across the Finnish border into the USSR by the OGPU’s Operation Trust, a fictitious monarchist underground used to deceive émigrés and Western services. He was arrested and executed near Moscow on November 5, 1925. His fate became one of the best-known results of Trust, a model for later Soviet deception and penetration operations.

Sources

• Jeffery, Keith. The Secret History of MI6, 1909-1949. Penguin Press, 2010.
• Cook, Andrew. Ace of Spies: The True Story of Sidney Reilly. Tempus, 2004.
• Andrew, Christopher, and Vasili Mitrokhin. The Sword and the Shield: The Mitrokhin Archive and the Secret History of the KGB. Basic Books, 1999.

Summary entry. A fuller, document-based profile is in preparation.