Sidney Reilly, the so-called Ace of Spies, was a womanising British secret agent who claimed to be Irish but was in fact Russian. A bitter opponent of the Bolsheviks, he approached MI6 offering his services. Mansfield Cumming, the head of the British secret service, spotted immediately that Reilly was a crook describing him as 'very clever - very doubtful' but also recognised his genius as a spy. Reilly orchestrated a plot to overthrow the Bolshevik leadership which failed, but won the Military Cross for his daring operations undercover in Moscow. He returned to London a hero. At least two bigamous marriages were followed by a final mission to Russia in 1925, but Reilly was killed in a sting operation by the Soviet secret service.