Major RAF Victory, Later Commemorated as Battle of Britain Day

15 September was a day of heavy and sustained fighting.

The Luftwaffe had flown over 1,000 sorties. Euphoric British pilots and anti-aircraft gunners claimed a magnificent total of 185 victims. Although the real count was 60, the highest German losses since 18 August, for once figures did not matter. It was obvious to both sides that German tactics had failed. The German Air Force had not swept Fighter Command from the skies. It had not gained air supremacy. Although fighting continued, sometimes heavily, for another few weeks into October, the action on 15 September had seen an overwhelming and decisive defeat for the Luftwaffe. For this reason, this date is celebrated in the United Kingdom as Battle of Britain Day.

On 15 September two massive waves of German attacks were decisively repulsed by the RAF, with every single aircraft of 11 Group being used on that day. The total casualties on this critical day were 60 German and 26 RAF aircraft shot down. The German defeat caused Hitler to order, two days later, the postponement of preparations for the invasion of Britain. Henceforth, in the face of mounting losses in men, aircraft and the lack of adequate replacements, the Luftwaffe switched from daylight to night-time bombing.

On 13 October, Hitler again postponed the invasion "until the spring of 1941"; however, the invasion never happened, and October is regarded as the month in which regular bombing of Britain ended. It was not until Hitler's Directive 21 was ordered on 18 December 1940, that the threat of invasion finally dissipated.