(June 1940–April 1941) Series of intense raids directed against Britain by the German air force in World War II .
The air attacks, intended to prepare the way for a German invasion, were directed against British ports and RAF bases. In September 1940 the attacks turned to London and other cities in a "blitz" of bombings for 57 consecutive nights, which was followed by intermittent raids until April 1941. The RAF was outnumbered but succeeded in blocking the German air force through superior tactics, advanced air defenses, and the penetration of German secret codes.