Elyesa Bazna was the highest-paid spy in history. Working for the British ambassador in Ankara in 1943, Bazna photographed top-secret documents and sold them to the Nazis. So started his career as a 'walk-in', a freelance spy whose loyalties lay with the highest bidder. His codename was Cicero. But a beautiful woman was to end it all.

Cicero was compromised by an American-controlled agent working at the German Embassy, who obtained his code name and discovered that he was working at the British Embassy. He fled and narrowly avoided being captured by the tipped-off British. Finally free, he realised his money was worthless – most of it was counterfeit, produced by the Nazi scheme Operation Bernhard.

Mark Simmons weaves together personal accounts by the leading characters and information from top-secret files from MI5, MI6 and the CIA to tell the astonishing story of Agent Cicero.