New instructions from Air Vice Marshal Park came into effect in No 11 Group today.

They were aimed at countering the shorter timescale between warnings from radar stations and raiders appearing over London, especially now that some German fighters were carrying bombs.

Park addressed the time taken for squadrons and other formations to climb from the ground to an effective height. He stressed. “Bitter experience has proved time and again that it is better to intercept the enemy with one squadron above him than by a whole wing crawling up below, probably after the enemy has dropped his bombs.”

London and Birmingham suffered heavy attacks today. Severe damage was done to the capital’s railway system, including hits on Waterloo station and various points on the underground network.