Agent Jack by Robert Hutton review – MI5’s secret Nazi hunter

The story of the spy who masqueraded as the Gestapo’s man in London – and the British plots to help Hitler

Fear of an enemy within has become a defining aspect of modern history. Britain, having “stood alone” against Hitler, took pride in its defiance of fascism – after the internment of Oswald Mosley and his goons it was assumed that the country was safe from the Nazi contagion. But following the release of declassified MI5 files in 2014 that assumption collapsed, for in them was revealed an enemy hiding in plain sight. Some were Germans domiciled in Britain, but most were ordinary British citizens willing to help and even risk their lives for the Nazi cause.

Robert Hutton’s deeply researched, often astounding book describes how a loose network of homegrown fascists plotted to undermine wartime Britain, and explains the ingenious way MI5 attempted to neutralise them. It places centre-stage ...