In May 1940, Britain was at a moment of great peril. Winston Churchill had just become Prime Minister and was facing the prospect of a Nazi invasion. But it wasn't just Hitler that concerned him. There was also the threat from Britain's own fascist sympathisers: the so-called 'fifth column' that could undermine Britain's war effort from within. Within a few days of Churchill becoming Prime Minister, MI5 swooped on addresses in central London. The targets were members of a secretive organisation called The Right Club, an extreme pro-Nazi society led by an aristocrat and MP in Churchill's own party, Archibald Ramsay. Ramsay's Right Club wanted to bring down the government and forge an alliance with Hitler. When they stumbled across stolen secret documents that could discredit Churchill and prevent America from entering the war, they knew they'd hit the jackpot. What they didn't know was that one of Britain's most brilliant spy-masters, Maxwell Knight, was setting a trap for them. If he was successful his move against Ramsay's Right Club would enable him to round up over 1000 of Britain's Nazi sympathisers and eliminate the enemy within. The compelling cloak-and-dagger story of how Churchill and MI5 hunted down The Right Club reveals a little-known aspect of war-time Britain: a murky world of fascist aristocrats, disaffected foreign nationals and spies.