Klop Ustinov was Britain’s most ingenious secret agent, but he wasn’t authorised to kill. Instead, he was authorised to tell tall tales, bemusing and beguiling his enemies into revealing their deepest, darkest secrets. From the Russian Revolution to the Cold War, he bluffed and tricked his way into the confidence of everyone from Soviet commissars to Gestapo Gruppenführer.

In Klop: Britain’s Most Ingenious Secret Agent, journalist Peter Day brings to life a man descended from Russian aristocrats and Ethiopian princesses but who fancied himself the perfect Englishman. His codename was U35 but his better-known nickname ‘Klop’ meant ‘bedbug’, a name given to him by a very understanding wife on account of his extraordinary capacity to hop from one woman’s bed to another in the service of the King.

Frequenting the social gatherings of Europe in the guise of innocent bon viveur, he displayed a showman’s talent for entertaining (a trait his son, the actor Peter Ustinov, undoubtedly inherited), holding a captive audience and all the while scavenging secrets from his unsuspecting companions. Klop was masterful at gathering truth by telling a story; this is his.