On this date in 1940, the Battle of Britain was approaching its height. The German Luftwaffe had yet to shift from its strategy of bombing the Royal Air Force’s airfields toward London in what would come to be known as The Blitz.

As a result, massive dogfights occurred nearly every day over the south of England and today one of the most difficult, and bloodiest, days of the entire conflict took place.

Five days before, German forces had launched what was called Adlertag, or “Eagle Day”, what was until that time the largest effort made to destroy the Royal Air Force in the air. The entire objective, of course, was to deny England control of its airspace so the Germans could launch Operation Sea Lion, which was the code name for the invasion of the British Isles.

The RAF gave much better than they got in the air that day, destroying 48 German fighters for the loss of 13 of their own. However, RAF planes destroyed on the ground evened the score. As such, the Germans, who used Adlertag as the opening day of a larger offensive called Unternehmen Adlerangriff (“Operation Eagle Attack”), would have to find another way to achieve their objective.

Five days later, the Germans were back again.

They based their attack on a rather remarkable failure of intelligence. The Germans had estimated the RAF was down to less than 300 serviceable aircraft. In fact, the number was 855, with another 289 either under repair or in storage, and so when the Germans of Luftflotte 2 launched their attack on the southeast airfields, the British defense had some real teeth to it.

The first blow fell on RAF Group 11, commanded by a man who would eventually become Sir Keith Park KBE. Airfields at Biggin Hill and Kenley were among the first to come under attack from German KG (bomber geschwader, or squadrons.) The British had plenty of early warning from radar that German forces were forming up over Calais and were ready to greet them in force.

The British, too, were operating with flawed intelligence. The Germans sent 108 fighters and 150 escorting fighters over England, but the British thought about 350 aircraft were headed their way. This led to some of the largest air battles ever recorded to that time.

That started a wild day of combat in which the Germans lost 69 aircraft and the British 68, again many being casualties on the ground. The losses on both sides were so severe that the day soon earned the sobriquet of “The Hardest Day” in subsequent histories of the battle.

The greatest casualty to the British, however, wasn’t any single airplane, but rather their advanced radar station at Poling, which was a key to the entire defense of the south coast. A patchwork of other radar stations helped ease the pressure on the early warning system until Poling could be repaired, but 28 servicemen were killed in the raids as well.

That started another battle, that of propaganda. Instead of admitting the loss of nearly a quarter of its attacking force, the Germans only admitted to 36 aircraft lost, slightly more than half the actual total. Meanwhile, the British claimed they had destroyed 150 German attackers, which was over twice the actual total.

On the other side, the British admitted 23 losses, about a third of their actual total, while the Germans claimed 147 British aircraft destroyed, over twice the actual number lost.

While this was not uncommon in wartime, it did serve to illustrate the need for propaganda to convince the home fronts in both nations that the air war was going well.

It wasn’t until a month later — on September 15, 1940, the date known as “Battle of Britain Day” in England, that the Germans would lose an additional 56 aircraft in exchange for 28 British fighters. The next day, the Germans changed their tactics and began bombing London.

On that September day, the legendary British fighter pilot Ray Holmes was rousted out of his bath to scramble to fight attacking German aircraft. He saved Buckingham Palace from being bombed by ramming a German bomber after running out of ammunition. He went down wearing the robe he threw on when scrambled, and survived. As he was being taken to Chelsea Barracks, he was approached by a major who asked him, “Excuse me, old boy, but do you always fly dressed like that?”

Happy Sunday and enjoy today’s open thread!