policy, it was obvious that area bombing would cause large-scale civilian casualties. With the technology available at the time, the precision bombing of military targets was possible only by daylight, and it was difficult even then. Daylight bombing raids conducted by Bomber Command involved unacceptably-high losses of British aircraft, and bombing by night led to far lower British losses but was of necessity indiscriminate because of the difficulties of nocturnal navigation and bomb aiming. 1940 to 1943 Before 1941, Berlin, at from London, was at the extreme range attainable by the British bombers then available to the Allied forces. It could be bombed only at night in summer when the days were longer and skies clear—which increased the risk to Allied bombers. The first RAF raid on Berlin took place on the night of 25 August 1940; 95 aircraft were dispatched to bomb Tempelhof Airport near the center of Berlin and Siemensstadt, of which 81 dropped their bombs in and around Berlin, and while the damage was slight, the psychological effect on Hitler was greater. The bombing raids on Berlin prompted Hitler to order the shift of the Luftwaffe's target from British airfields and air defenses to British cities, at a time during the Battle of Britain when the British air defenses were becoming exhausted and overstretched. In the following two weeks there were a further five raids of a similar size, all nominally precision raids at specific targets, but with the difficulties of navigating at night the bombs that were dropped were widely dispersed. During 1940 there were more raids on Berlin, all of which did little damage. The raids grew more frequent in 1941, but were ineffective in hitting important targets. The head of the Air Staff of the RAF, Sir Charles Portal, justified these raids by saying that to "get four million people out of bed and into the shelters" was worth the losses involved. The Soviet Union started a on Berlin on 8 August 1941 that extended into early September. Medium Navy bombers, accompanied from 12 August by Army bombers, conducted ten raids from Saaremaa island to Berlin with 3–12 aircraft in each raid, fifty in total reaching Berlin. Heavy Army bombers, operating from near Leningrad, executed one raid to Berlin on 11 August, with only few machines reaching the target. In total in 1941, Soviet aircraft dropped of bombs on Berlin. Combat and operational losses