Yet only four years earlier, it had been a very different picture. Most of the RAF was abroad guarding colonial possessions against rebel tribesmen. The RAF in Britain, known as the Metropolitan Force, was dedicated to recruitment and training. There was no force dedicated to the defence of the realm.
Fighter Command was born in 1936 on the sudden realisation that Adolf Hitler’s Nazi Germany just might be an aggressive force that could be an enemy in some future war. Some, notably a backbench MP and former government minister named Winston Churchill, had been saying as much for years but it was not until an official government committee reached the same conclusion that anything much was done.
Even then the growth of the RAF was hampered by the fact that the Foreign Office persuaded the government to accept their estimates of Germany’s armed strength over the estimates of the War Office. The fact that the Foreign Office figures were simply those announced by Hitler himself was not made clear at the time.
Perhaps because the Foreign Office figures indicated that Germany would not be ready to fight a war before 1942, that was the date set in RAF plans for when Britain would be ready too.
from "Heroes of RAF Fighter Command in Kent" by Rupert Matthews.