Fact File : Thousand-bomber Raids
30 May, 1 June and 25 June 1942
Theatre: Western Europe
Location: Cologne, Essen and Bremen, western and central Germany.
Players: Britain: Air Marshal Arthur Harris's RAF Bomber Command.
Outcome: Massive destruction to German factories and homes, particularly in Cologne.
'The idea of area bombing was to attack an aiming point which lay at the centre of a large area whose destruction would be useful. It was, in other words, a way of making bombs which missed the aiming point contribute to the destruction of the German war machine. Since nearly all the bombs were missing the aiming point, there was a certain logic about the idea.' - Noble Frankland, historian and Bomber Command veteran
Sir Arthur Harris (1892-1984), nicknamed Bomber Harris, the commander-in-chief of the RAF's Bomber Command©
Arthur Harris was a consistent and forthright advocate of the destruction of enemy morale through overwhelming attacks on civilian targets. The strategy predated Harris; as early as 1917 General Jan Smuts, advising Lloyd George on Britain's air defences, anticipated that the 'destruction of industrial and populous centres on a vast scale' through aerial bombing might soon become the main weapon of war.
Between the wars there were repeated attempts, some British-led, to ban the bombing of civilian targets in accordance with the 1907 Hague Convention; none succeeded.
Harris's preference for area bombing was initially supported by limitations in the bombers' navigation and target-location capabilities, which made precision bombing impossible. Early in the war, even city bombing could not be undertaken with any confidence; the Butt Report of 1941 concluded that less than one in three of all bombers had got within five miles of their appointed target. In the smoky and densely populated Ruhr valley, this figure dropped to one in ten - or one in 15 on moonless nights.
In May 1942 Harris was directed, with an ambiguity which came to typify Bomber Command's orders, to launch raids on industrial centres while targeting 'the morale of the enemy civilian population'. Where possible the raids had to use GEE, an early radar-based navigational aid. GEE could not pinpoint an aeroplane's position to the degree required for precision bombing, but it stopped bombers straying wildly off course.
Harris took the opportunity to demonstrate the potential of area bombing by replicating the morale-destroying Lübeck raid on a larger scale. The target was the industrial city of Cologne; the tactic was to overwhelm city defences by sending 1,000 bombers overhead in the space of 90 minutes.
The psychologically significant figure of 1,000 aircraft was not easy to achieve. Harris eventually assembled a force of 1,047 bombers by dint of including aircraft used for training, with crews who were themselves not fully trained. In view of the potential for losses, this was an immense gamble.
On the night of 30 May, 890 bombers reached Cologne. The bombing did not create a general firestorm, as in Lübeck, but it did cause massive damage. According to German figures, 469 people were killed and 45,000 made homeless. Only 41 aircraft were lost. Harris followed through with a second raid two nights later, fielding 956 bombers against the industrial town of Essen. Due to the target-acquisition problems endemic to the Ruhr valley, relatively little damage was done.
A third raid, in which 960 bombers targeted the coastal town of Bremen, took place on 25 June. Damage was more extensive than in Essen, although it fell far below the levels of the Cologne raid. While some military installations and several shipyards were hit, most of the damage was to residential areas.
In the context of an area bombing strategy, the 1,000-bomber raids could be seen as a success. The policy had full government support; Harris was knighted shortly before the Bremen raid. However, the efficacy of area bombing still remained to be demonstrated.
The fact files in this timeline were commissioned by the BBC in June 2003 and September 2005. Find out more about the authors who wrote them.