The Bf-109F threat (Me-109F)

The Bf-109F (the official history calls it the Me-109F) was present in enough strength in early 1942 that the fighter plane was causing problems for the British over the desert (as many problems as it was causing the Russians). British pilots tended to be under trained in the desert and they were not very accurate in firing. As part of the measures implemented to better counteract the Bf-109F, British pilots started "shadow firing", rather than firing at a towed drogue. Radar coverage had improved to better detect low-flying Bf-109F's and there were more ground observers equipped with radios. For more flexibility and to reduce the number of targets for the German planes, the British instituted patrols with 4 to 6 fighters. This is based on the account in Vol.III of the Official History.