The Bombers and the Bombed: Allied Air War Over Europe 1940-1945

by Richard Overy

The proportion of incendiaries carried by German bombers was known to vary between 30 and 60 percent, concentrated in the first attack groups, while RAF bombers carried between 15 and 30 percent, diluted throughout the force. The critical problem was how to drop enough incendiaries to create fires that ran out of control, which meant smothering an area with firebombs. The attack on the City of London on December 29, 1940, was used as the model. The raid started twenty-eight conflagrations, fifty-one serious fires, 101 medium fires, and 1,286 small ones, and it was this level of assault that could be expected to overwhelm the emergency services.92 Detailed evidence from Britain’s other blitzed cities suggested that incendiary bombs had five times the destructive potential of heavy explosive per ton. They were best used, it was suggested by Air Intelligence, against cities with narrow streets and wooden structures. Germany’s old town centers were “ideal targets for large-scale incendiary attack” because German urban areas were denser and taller than their British equivalents. A salvo of 30,000 British four-pound incendiaries dropped in twenty minutes was regarded as a necessary minimum, though much larger quantities were found to be necessary later on. High explosive was needed to reduce the water supply and ventilate the buildings.