It has gone down in history as the most daring RAF operation of the Second World War. With its mix of heroism and technical ingenuity, the Dambusters Raid became a lasting symbol of Britain's gallant fight against the Nazi regime ... Yet it has now emerged that Air Marshal Sir Arthur "Bomber" Harris, one of the chief architects of the raid, was privately scathing about its effectiveness. Research in the archives of the Harris papers, stored in the RAF Museum at Hendon, has revealed that he privately thought the assault on German dams was a waste of men and aircraft.