During the Battle of Britain some senior officers such as Vice Marshal William Sholto Douglas, assistant chief of air staff, were highly critical of the strategy promoted by the head of Fighter Command, Hugh Dowding and Vice Marshal Keith Park, the commander of No. 11 Fighter Group. Douglas, who was supported by Trafford Leigh-Mallory and Douglas Bader, argued that RAF fighters should be sent out to meet the German planes before they reached Britain. Park and Dowding rejected this strategy as being too dangerous and argued it would increase the number of pilots being killed.

Air Chief Marshal Charles Portal, the new chief of the air staff, agreed with William Sholto Douglas and in November 1941, he removed Keith Park and Hugh Dowding from their posts. Douglas had the added satisfaction of taking over from Dowding as head of Fighter Command.

William Sholto Douglas now developed what became known as the Big Wing strategy. This involved large formations of fighter aircraft deployed in mass sweeps against the Luftwaffe over the English Channel and northern Europe. Although RAF pilots were able to bring down a large number of German planes, critics claimed that they were not always available during emergencies and prime targets became more vulnerable to bombing attacks.