 The appointment of Arthur Harris, Air Officer Commanding (AOC) Bomber Command changed the nature of the night war.Area bombardment became the tactical method of destroying a target after the damning Butt Report in 1941.The result of improved navigational aids and new heavy bomber designs, the British carried out destructive air attacks on German cities, beginning with the attack on Lübeck in March 1942, and then the bombing of Hamburg in July 1943.