Sunday the 15th of September 1940
Day: The climax of the Battle, remembered as The Battle of Britain Day. A maximum effort by the Luftwaffe, with layered groups from 15,000 to 26,000 ft, heading for London with diversions and feints. Escorting fighter screens positioned upward to 30,000 ft. Once this air armada is set on its course, other raids set off for Portland / Southampton. Most raiders continued to climb when they were inland, and then in full sight of British radar split into numerous groups on different headings. Determined defence by Fighter Command, which puts up 24 squadrons during the day, prevents concentrated bombing by these groups, and by the time they have split up under attack and been backed by further incoming groups, the whole airspace over South-Eastern England appears filled with enemy formations. Bombing is generally sporadic and inaccurate, and spread over a far larger area than planned. Two bombs landed on Buckingham Palace but failed to explode. Those two U.X.B's were a godsend for the British propaganda machine.
This was the day Winston Churchill visited 11 Group's headquarters at Uxbridge with his wife and met Park's famous answer to his question about reserves: "There are NONE".

The BBC reported 185 enemy aircraft destroyed, the actual score was about 60

Night: There was a heavy attack on London. There were smaller raids on Cardiff / Bristol and the Manchester / Liverpool area's

Losses: Luftwaffe 56: Fighter Command 27.

Weather: Fine, though some light cloud during the middle of the day. Early mist and haze give a hint of likely large-scale attacks