On July 1940, the situation looked dire for Great Britain. It had taken Germany less than two months to invade and conquer most of Western Europe. The fast-moving German Army, supported by panzers and Stuka dive bombers, overwhelmed the Netherlands and Belgium in a matter of days. France, which had 114 divisions and outnumbered Germany in tanks and artillery, held out a little longer but surrendered on June 22. Britain was fortunate to have extracted its retreating expeditionary forces from the beaches at Dunkirk.
Britain itself was next. The first objective for the Germans was to establish air superiority as a precondition for invasion. The Luftwaffe estimated haughtily that it would be able to defeat the Royal Air Force's Fighter Command in southern England in four days and destroy the rest of the RAF in four weeks.