232: Battle of Britain Day

Description

On September 15, 1940—Battle of Britain Day—the Luftwaffe launched what would become the climactic daylight assault of their campaign against Britain. In a desperate final effort to enable Operation Sea Lion, the German invasion of Britain, over 500 bombers escorted by hundreds of fighters targeted London’s railways and dockyards in two massive raids. However, RAF Fighter Command rose to meet them with unprecedented coordination, deploying every available squadron in a series of perfectly timed intercepts that turned the skies above London into absolute mayhem. Despite wildly exaggerated victory claims on both sides, the day’s fighting proved that Fighter Command was far from the spent force the Germans had hoped, while the Luftwaffe’s mounting losses and fuel limitations exposed the futility of their campaign. As weather closed in and Hitler postponed Sea Lion indefinitely, September 15th marked not just the end of the daytime Battle of Britain, but the beginning of a new phase—the Blitz.

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Summary

Hello everyone and welcome to History of the Second World War Episode 232 - The Battle of Britain Pt. 7 - Battle of Britain Day. This week a big thank you goes out to Aiden, Cole, and Zach for supporting the podcast by becoming members. Members get access to ad-free versions of all of the podcast’s episode plus special member only episodes roughly once a month. Head on over to historyofthesecondworldwar.com/members to find out more. On September 15, 2024 84 years to the day after the first Battle of Britain day, I was on the way to IWM Duxford for the Battle of Britain day airshow. It was an absolutely incredible day, the weather was perfect, so many interesting historical aircraft were flying . The sounds of Hurricanes and Spitfires in the air, wonderful. But the perspective of me at an air show is completely different than what it would have been on September 15, 1940 the actual Battle of Britain day. On that day the Luftwaffe would launch what has come to be seen as the climax of the day time battles of Britain that had started months earlier. The target of the German bombers for the day was a raid once again on London, and once again RAF Fighter Command would rise to meet them in what would be one of the most costly raids of the entire campaign. But in some ways, rather than a triumphant climactic class in the skies above Britain, the day was more of a disappointing end to a long campaign. In what was to be their final effort to in some way save the plans for the invasion the Luftwaffe put in a maximum effort day, but even this maximum effort would be smaller than some of the most active days earlier in the campaign. The Luftwaffe was simply running out of men, aircraft, and time. At the same time, Fighter Command was able to still largely do what it had been doing for weeks by the middle of September, and in roughly the same numbers. This would result in a series of actions on September 15th during which the entirety of the Luftwaffe campaign of the previous months could be called into question, they simply were not getting the job done.

September 15th would start off to be a bit hazy, bit of clouds, but it would eventually provide perfect weather for what the Luftwaffe was planning to do on the day. This would be the day for the final grand assault on London, code named Valhalla, during which Kesselring’s Luftflotte 2 would make a maximum effort raid on London. The plan was to roughly match the same tactics that the Luftwaffe had been using for most of the battle, with a smaller initial raid that was heavily escorted by fighters and then a larger raid following it up for the main attack. In theory the RAF fighters would swarm on the first raid, to be met by 109s and would then be out of position and unavailable to meet the real strike that followed behind. For this effort would be arranged around 500 bombers, 100 Bf-110s and somewhere between 400 and 500 109s. Their target was the some of the railways around London, with the goal of destroying them to prevent them from being used to move troops southeast out of London towards the coast. Very much an invasion preparation mission. To meet this attack the 310 fighters available in 11 group, 194 in 12 group, and 126 in 10 group. While not all of these were in position to assist in an attack on London, if even half of 12 Group could join the fight the number of single engine fighters would be almost even.

The first raid would be detected by British radar just a few minutes after 11AM, this was the made up of Dornier-17s with heavy escort. The Dorniers were an amalgamation of different bomber groups, because by this point in the campaign many of the bomber groups were far below establishment due to combat losses and maintenance issues. This did not necessarily impact their performance, but it is noteworthy as a way of understanding the state of the Luftwaffe by the middle of September. All the British knew was that there was a raid, and it was already quite large, and so Park’s 11 Group began to get squadrons into the air and positioned to meet them. The first squadrons dispacted were 92 and 72 squadrons from Biggin Hill, with the goal of getting up to 25,000 feet as quickly as possible. Their job was to launch the first attack against the escorting fighters, distracting them and also bringing them down to a lower altitude during the ensuing dogfight. They would be followed by 603 which would arrive slightly later and would be at 20,000 feet altitude in the hopes that this would position them to reinforce the first two squadrons at the right time. 6 more squadrons were put in the air between 1130 and 1145, with most of them positioned on the expected path towards London. The ability to orchestrate an interception like this was one of the major problems that the Luftwaffe had faced as they had moved their bombing targets further towards London, the RAF often had more time, and instead of the mad scrambles to get at the bombers that had been required for coastal targets they could instead plan to peel the layers off the bomber protection over time. First it was the high escorts, which were positioned to dive down on any British fighters that attacked the bombers, then it was the close escorts that were flying with the bombes, and then finally the target would be the bombers themselves. If everything went well all of this would happen even before the Germans reached their target. Along with the squadrons of 11 Group 12 Group would be brought into the mix as well, with the goal of bringing in multiple squadrons in one Big Wing which would hopefully intercept the bombers from 20,000 feet around Horncurch. If the interception worked they would be perfectly positioned to dive down on the bomber squadrons after their fighter escorts had been distracted and disrupted.

The actual interception of the raid would go mostly as planned. The German bombers were a bit behind schedule, which meant that some of the free hunting Luftwaffe fighters that had been sent ahead had to return to base before the bombers arrived. But then once the bombers were over Ashford, about 15 kilometers from the coast, they were spotted by 92 Squadron which went in for the attack, quickly joined by 603 squadron as well. During the dogfight that would develop 6 109s would be shot down. About five minutes after 92 squadron engaged the high fighter escorts two squadrons from Kenley, 253 and 501, often referred to in history as the Kenley Wing, made a direct attack on the bombers and then quickly became engaged with the close bomber escorts. After their attack 41 and 66 Squadron arrived, with the two squadrons splitting their focus 41 on the escorts and 66 on the bombers. Just as that attack was complete 4 more squadrons in two different groups arrived from two different directions. 257 and 504 and then 605 and the 1 Canadian squadron would arrive with most of them being engaged by the remaining escorts. During this attack 4 Hurricanes would be shot down. It would be at around this moment, just after noon that the squadrons from 12 group would arrive. They arrived at 25,000 feet, above all of the action that was occurring below them. For fighter pilots during the Second World War this was perfect, and they took the time to position so that they came in from behind the German squadrons, and would have the sun at their backs. After most of the 11 Group’s fighters had made their attacks and were on their way back to base the three squadrons of Hurricanes and 2 of Spitfires would dive onto their targets. Just as this was happening the German bombers were approaching their targets and dropping their bombs, on the Clapham Junction railway, which they would hit and would do damage to. but with the arrive of 12 Group they were now in trouble. With their fighter protection pushed away by the earlier squadrons and the seeming constant arrive of more and more British fighters the Dorniers would have to fight for their lives all the way back to the channel. 4 more squadrons from 11 Group joined the 5 from 12 Group in the hunt, and there was a point where there were so many British fighters in the area that they were not able to all attack at the same time. To prevent collisions they had to queue up to wait for their turn to launch their attacks. Eventually the German bombers would arrive back under the protection of additional 109s that had been sent to escort them back to France, but the damage was already severe. During all of this action Fighter Command had lost 13 fighters, a serious number but it was matched by 12 109s and 6 german bombers which was around 12% of the entire German raid. Both sides would drastically exaggerate the number of enemies that they shot down, particularly once 12 Group’s squadrons involved and there were so many British fighters that a single kill could be counted 9 times. But while the specifics were not entirely clear, what was known to the Germans is that they had been met by very large numbers of British fighters. The hope was that by the middle of September Fighter Command was almost a spent force, that it was down to its last dregs of pilots and aircraft. And yet instead of appearing that way against the raid they had mounted a constant series of attacks from almost the moment that the German bombers had crossed over the coast. It was surprising and demoralizing, especially for the bomber crews that had been told to expect much lighter resistance.

While the first raid of the day had been costly for the Luftwaffe, it had done its job by bringing out as much of the strength of 11 Group as possible. This would theoretically allow the second, and larger raid of German bombers to reach their targets with far fewer enemy fighters in the air to stop them. The target for the second raid was a series of Dockyards in the East End of London. These docks would be targeted by 114 German bombers from a variety of different Bomber Groups, at this point many of them were so worn down that bringing them together was the only way to achieve full group numbers. And they would be escorted by almost 350 Bf-109s and 20 Bf-110s. There was a problem though, because of the very heavy fighter escort for both of the day’s raids, many of the 109 groups had to participate in both escort missions. This was within the capacity of the pilots, that was not the problem, but there were delays on the ground when it came to getting their planes refueled and rearmed. This cut down on the number of fighters that would be available for the mission, from the planned numbers of greater than 400 down to 340, but it also delayed the raid slightly. This was critical because, at the same time that the German fighters were being rearmed and refueled, the exact same thing was happening on the British side. They were also trying to bring the returning fighters of Fighter Command back into readiness as quickly as possible. To add to the Luftwaffe’s problems, the British fighters also arrived back at their airfields much sooner than the Germans, they had been in some cases in combat almost on top of them . And if the Germans did not launch their second raid fast enough, the distractions caused by the first raid would be for nothing because the British would be prepared for the second arrived.

The raid was first detected by British radar at 1:45PM, with three large groups of aircraft detected, making this clearly a larger raid that what had happened just 4 hours before. The plan for this raid was similar to what had been done the first time, with the majority of the British fighters scheduled to intercept the raid over London or on its way home. This had the obvious downside of making it more likely that the German bombers would actually drop their bombs, but this short term issue was exchanged for the difficulties faced by the German fighters over London. By the time the German raids reached London the 109 pilots had to keep a very close eye on their fuel gauges, they only had a very limited amount of fuel that they could burn in dogfights over the British capital if they wanted to make it back to their bases. This was perfect for Fighter Command, because their target was the bombers, so a 109 that had to turn around a head back to base was just as good, at least at the moment, as one that was shot down. The fact that the target of the raid was almost certainly London just made everything easier at 11 Group Headquarters, with Park able to better plan and arrange his squadrons for the intercept. He would launch every squadron in 11 Group, with 183 Spitfires and Hurricanes eventually in the air and converging on the German bombers. He would also of course request assistance from both 12 and 10 Groups, it was truly a maximum effort for Fighter Command. On this occasion Churchill was at 11 Group headquarters to observe what was happening, which resulted in the exchange that has become somewhat famous, with Churchill asking “What reserves have we got?” when looking at the map plots and the converging forces. Park would answer “there are none” because he had already ordered every fighter into the air. Park would later say that this answer, and the situation as a whole would cause Churchill to look ‘grave’, which Churchill would address in some of his later writings. Using the typical Churchillian flare he would write: ‘What losses might we not suffer if our refuelling planes were caught on the ground by further raids of “40 plus” or “50 plus”! The odds were great; our margins small; the stakes infinite.’. While these concerns were legitimate, having a large number of fighters caught on the ground would have been a problem for the RAF, it was a lower risk than perhaps he is insinuating because that would have went against the Luftwaffe’s recent operating habits.

The German bombers were arranged in three different groups, each with their own dockyard target in London, and many of them would be intercepted by their first squadrons of British fighters on the outskirts of the city. They then could do nothing other than continue to fly towards their targets as quickly as possible so that they could drop their bombs and turn for home. Most of the bombers would reach a target to drop their bombs on, even though they were not always able to drop them on the docks that they were aiming for. Part of this was due to the general inaccuracy of bombing at high altitude and speed, but one of the groups simply could not see their targets due to clouds and so they just dropped their bombs on some residential areas in southeast London. All the time that they were looking for an bombing targets they were under attack, and the Fighter Command squadrons were just swarming both the bombers and the escorts. It is almost difficult to convey just how fast and chaotic the action was during the raid. 27 Spitfires of 41, 92, and 222 Squadrons attacked some of the high escort fighters, then 37 Hurricanes of 213, 607, 501, and 605 Squadrons moved in on one bomb group, at the same time 249 and 504 squadrons attacked another bomber formation joined shortly by 46 and 603 squadrons, for a total of 50 Hurricanes and 13 Spitfires among the four, elsewhere 20 Hurricane’s and 21 Hurricanes of 66 and 72 squadrons were attacking the bombers targeting the Royal Victoria Docks, at the same time 23 Hurricanes of 73, 253, and 303 Squadrons were attacking those targeting the Surrey Commercial Docks. It was absolute mayhem, with a seemingly constant stream of Fighter command aircraft attacking either the German fighter or bomber formations, with the 109s often just completely overwhelmed both by numbers and the variety of directions that the Hurricanes and Spitfires were arriving from. And that was even before the 12 Group Big Wing arrived with 47 additional fighters that all came in together, although they were 30 109s ready to meet them. Faced with so many threats the fuel problems for the German fighters rapidly became acute, and eventually they had no choice but to start heading back home. The German bombers were left alone, and still the RAF fighters kept coming, with 12 Hurricanes and 25 Spitfires of 238, 602, and 609 squadrons coming into action against the defenseless bombers. All that the Dornier and Heinkel bombers could do was fly as quickly as possible to meet up with their fighter escort that would meet them on the return leg, but making it there would cost them 18 bombers. And then it was over and pilots in both the RAF and Luftwaffe began to return to base, on the British side the ground crews once again frantically worked to turn around squadrons to bring them back to readiness. At 11 Group headquarters at Uxbridge, where the exact status of every squadron was tracked, statuses began to change to Ordered to Land, then to Landed and Refueling, and then eventually to “At Readiness”. The possible third German raid never materialized during this process, which Churchill correctly identified as the most vulnerable point for the RAF during the day. After the danger seemed to be past, Park would be recorded as telling Churchill ‘I am very glad, sir, you have seen this. Of course, during the last twenty minutes we were so choked with information that we couldn’t handle it. This shows you the limitations of our present resources. They have been strained far beyond their limits today.’.

The initial story of September 15th, on both sides of the channel was of wildly exaggerated victory totals, as was the norm for such large aerial engagements. On the German side the initial estimates based on pilot testimony was that they they had destroyed a staggering 79 aircraft. Such a high estimate was already suspect given the existing understanding of remaining RAF fighter strength, and it was in fact heavily inflated. The real number was somewhere around 28-31 total aircraft destroyed, which was around a 1/3 of what the Germans officially estimated, which was honestly not their biggest miss of the campaign in terms of estimated vs actual. Instead it was the turn of the RAF to wildly inflate the total number of losses suffered by the enemy. The actual number of confirmed Luftwaffe losses on the day was 56, with 18 lost during the morning raid, 35 in the afternoon, and then 3 other single bombers lost on reconnaissance flights. These were heavy losses, particularly among the bombers which made up most of the losses. But the British claimed that they had shot down a staggering 185 German aircraft, which was theoretically possible, more than that had participated in the fighting, but was an outlandishly high number to claim. The challenge was the same as it always had been, when there were a lot of pilots and aircraft involved there was a heavy tendency for pilots to get confused. It is important to understand that it was not always the pilots being nefarious or trying to boost their victories artificially. The type of mistakes that could happen were if one pilots hit an enemy aircraft and say it started smoking and was clearly no longer combat capable he might claim that as a kill, but he would frequently lose sight of the enemy and turn his attention somewhere else, then another fighter could come in and engage the enemy just to ensure they were destroyed, and that pilot would also claim the victory. Those kind of mistakes were greatly amplified when there were so many aircraft all engaging in combat throughout the sky, particularly when large numbers of attacking aircraft make their attacks simultaneously. In retrospect the greatest issues in British estimations came from 12 Group and the arrival of its Big Wing of almost 50 aircraft at one time. 11 Group Commander Park was quite critical of the estimates provided by 12 Group, believing that they were clearly boosting their score due to the ongoing debate between Park and 12 Group commander Leigh-Mallory about the best way to organize their squadrons to meet the German raids. It was difficult to push back against the inflated estimates though, if only because everybody in the British leadership wanted a stunning victory, it was really really good for propaganda and morale. And so the official British figure would be 185, even if it was difficult to support, and in fact after the war the official figure would be drastically revised down to 60 which was much closer to the actual 56. Regardless of their losses, the German bombers did get through to their targets, dropping 110 tons of explosives and 108 incendiary devices either on their targets or on nearby civilian infrastructure. The damage caused was heavy in those civilian areas, but no real issues were caused for the British war effort, with nothing of real military significance being greatly damaged.

Of course the RAF did not know that the 15th would be one of the last times that there would be mass Luftwaffe activity over Britain, and so they frantically prepared for another round of raids on the 16th. Park would refine his plans to meet another set of raids much like on the 15th, with decisions made to try and get the Spitfires at a greater altitude to better deal with the highest 109 groups as well as an engagement plan that would try to do a better job of peeling off the 109s to allow easier access to the bombers. He was also becoming more convinced that the best way to meet the massed German raids like those on the 15th the best idea was not to try and intercept them on the way in, and instead to let them drop their bombs and then swarm in when the bombers were starting to lose their fighter escort. The Luftwaffe was also not sure that the 15th was the end of their daylight operations, although on the 16th there would be no real raids, mostly due to the fact that poor weather moved in. Then on the 17th the weather was very poor again, and a new forecast made it clear that the bad weather was there to stay for at least a week. It would be these weather reports that would put the final nail in the coffin of Sea Lion, because the lengthy delay made it impossible to achieve the invasion before October, which was considered to be simply too late in the year for any success. We will dig into the decision a bit more over the next few episodes, but Hitler would officially postpone the invasion without providing a new date, although it was expected at the time that the operation would be revisited in the spring of 1941. For the Luftwaffe, this delay meant that essentially its Battle of Britain, as defined by its mission since mid-August of destroying RAF Fighter Command, was over. There would still be some fighter action and a few raids, but the large daytime bombing raids with the purpose of enabling Sea Lion were over. For the last two weeks of September there were several more smaller raids, but nothing like what had happened on the 15h. The final tally of aircraft lost was the Luftwaffe with 1,155 aircraft from July 10 to September 15th, and the RAF at 1,134. The larger number of Luftwaffe losses included a large percentage of the committed bomber groups, which was problematic for future bombing operations . A larger issue for the Luftwaffe was the fact that almost every single one of the pilots and aircrew from those aircraft were lost, either killed or having been taken prisoner in Britain. For a military service that would soon be trying to find every possible trained pilot to meet the growing requirements of two front war, such losses were problematic. But those issues were still in the future as the sun set on September 15, Battle of Britain day, because the Battle of Britain was about to change, and the Blitz was about to begin.