The Tirpitz, Hitler's greatest weapon, was reputed to be unsinkable and the battleship inflamed an Allied obsession: to destroy her at any cost. More than 30 daring operations were launched against the 52,000 ton monster. But still the Tirpitz remained a significant threat to Allied operations. It was not until November 1944 that a brilliant operation by RAF Lancaster Bombers, under the command of one of Britain's greatest but least-known war heroes, finally killed off Hitler's last battleship.