In the darkest months of the Second World War, Churchill approved what seemed to many like a suicide mission. Under orders to attack the St Nazaire U-boat base on the Atlantic seaboard, British commandos undertook "the greatest raid of all", turning an old destroyer into a live bomb and using it to ram the gates of a Nazi stronghold. Five Victoria Crosses were awarded - more than in any similar operation. Drawing on official documents, interviews, unknown accounts and the astonished reactions...