<DIV>To most people, the Blitz lasted from September 1940 to May 1941. However, in December 1943, the code breakers at Bletchley Park received intelligence that the Luftwaffe's bombers were gathering for a major new operation. The Luftwaffe named the campaign attacks Operation Steinbock and committed 524 bombers, including 46 He177 Greif four-engine heavy bombers making a debut over Britain. The RAF was now far better equipped to deal with the new attack with 127 Mosquitoes and the anti-aircraft guns were radar directed. On the evening of 21 January, 227 bombers took off bound for London. For the next four months, attacks continued on London, Hull, Bristol, and other targets. This was the Luftwaffe's final attempt to bomb Britain. Casualties in Britain totaled 1,556 killed and 2,916 seriously injured. The Luftwaffe lost 330 aircraft and their crews?for every five people killed on the ground, the raiders lost one bomber and four trained crewmen killed or captured.</div>