The Chronology: Page-44
Since first light on August 15th until the last squadron of Fighter Command landed on September 15th, the intensity of the air combat was at its peak. 201 Fighter Command aircrew had been killed during this period and 495 aircraft had been destroyed. This was an average of 6.29 pilots killed each day and 15.47 valuable aircraft lost or destroyed on a daily basis. If we take a look at the Luftwaffe figures, one can understand as to why Göring was not impressed. The Luftwaffe lost 1,132 aircrew and 862 aircraft. This averaged out at 35.37 aircrew lost each day and 26.93 aircraft lost or destroyed every day for the last 32 day period.
It was also during this 32 day period that things were at their most difficult and daunting for the Germans. First of all, they made the fundamental alteration regarding strategy, which did not benefit themselves but played into the hands of Fighter Command where it appears that it gave them a new lease of life. It was prompted by the overall success of Keith Park's policy of refusing battle, as far as possible, with German fighters and concentrating against their bomber force. 
We must also appreciate the fact that Germany was not producing the amount of new aircraft at the same rate as they were in Britain, a feat that all accolades must go to the Minister for Aircraft Production Lord Beaverbrook. If the battle were to continue for the next 32 days with the same amount of attrition, then the Luftwaffe would surely be a spent force. Aircraft production in Britain, despite the number of attacks on the aircraft factories, still managed on many occasions to produce more aircraft on a daily basis than were being shot down.
Then, if we look at total fighter production between week ending August 17th and week ending September 14th we will see that 43 Defiants were produced, 271 Hurricanes, 186 Spitfires, 26 Buffalo's and 3 Westland Whirlwinds giving Fighter Command a total of 1154 serviceable fighter aircraft. This is an average daily total output of 36.06, meaning that Beaverbrook's factories were producing a little over twice as many fighter aircraft that were being shot down. 
Even though these figures appear to be excellent, we have to appreciate the fact that Fighter Command did lose a considerable number of aircraft from mid August to mid September, coupled with the fact that hundreds more had been damaged and were undergoing repairs. We are fortunate in having these figures available to us, but at the time, such accurate figures were not available and unless German intelligence was on the 'mark' they would have had no idea of the situation, except for the fact that there were four or five times more British aircraft to meet the German armada of bombers than they had anticipated.
During the morning, just as the Luftflotten commanders were giving instruction of the impending days raids, and the crews were being briefed, a communiqué came through stating that "Operation Seelöwe" had yet again been postponed. It was due to the present circumstances, and the message was obviously under the direction of Hitler, he being the only one who could announce such a decision. Later, the German General Staff sent a message by radio to the commanding officer handling the loading and supply of troop-carrying aircraft in Holland. It gave the commanding officer the authorization to dismantle all of the air-loading equipment at all the Dutch airfields. Without this vital equipment, there could be no such invasion, and by the withdrawal of the air-loading equipment and possibly the barges at Antwerp, it appeared that this postponement was more like an abandonment.
In the deciphering rooms at Bletchley Park, the message was intercepted by Ultra loud and clear. Marshal of the Royal Air Force Sir Cyril Newhall stated to his ministry that with this great news of the air-loading equipment being ordered to disband, and with the unreliable weather conditions that could be expected for the remainder of the year, any planned invasion would now not take place, not in 1940 anyway. Again the Air Ministry put this down to their success of September 15th. (Some resources state that on this day, that Hitler abandoned the invasion indefinitely, this is not the case, the invasion was only postponed, but because of the coming winter, it was assumed that it would not take place during the rest of 1940). In Germany, Hitler's new directive stated that Operation Sealion could still be expected, even as late as October, but only if the air and weather conditions permitted, otherwise such an invasion could not now take place until 1941.
TUESDAY SEPTEMBER 17th 1940
Cold with squally winds especially in the Channel areas. Rain periods were to be expected in the south with the chance of a thunderstorm. The possibility of bright intervals expected during the afternoon.
There was very little activity during the morning period. Radar had picked up several small blips over the Channel, but these being either enemy aircraft flying singularly or in pairs were ignored by Fighter Command as they were probably just weather or photo-reconnaissance aircraft and caused no threat. One enemy bomber came very close over the town of Dover and the air raid warning sounded but the bomber flew along the coastline for a while before turning back out over the Channel towards its base.
1400hrs: A formation of Ju88s were detected heading in a northerly direction over Bristol. There target was believed to be the factory areas of north of Bristol. 152 Squadron Warmwell (Spitfires) were scrambled to intercept. One of the Ju88s was hit and it was further harassed by the Spitfires until it crashed near Warminster south-east of Bath. The pilot was killed while three others were captured, one of them being a Gruppe Commander.
1500hrs: With the brightening of the weather allowing better visibility, a large formation was detected crossing the Channel from Calais. As they crossed the coastline between Dover and Dungeness, the Observer Corps had trouble identifying them reporting that it was a large formation at great height. They could very well be forgiven, because the enemy formation was only flying at 15,000 feet, but they were a large contingent of Bf109s heading across the Kent coast.
11 Group dispatched at varying times a number of squadrons, most of them Hurricanes. 1RCAF Squadron Northolt (Hurricanes), 17 Squadron Debden (Hurricanes), 19 Squadron Duxford (Spitfires), 41 Squadron Hornchurch Spitfires), 73 Squadron Debden (Hurricanes), 213 Squadron Tangmere (Hurricanes), 257 Squadron Debden (Hurricanes), 303 Squadron Northolt (Hurricanes), 501 Squadron Kenley (Hurricanes), 603 Squadron Hornchurch (Spitfires) and 607 Squadron Tangmere (Hurricanes) some sources state that up to twenty squadrons were dispatched, but records were not available.
While it is not actually known where the target area was to be, the formation of Bf109s, accompanied by a small number of Ju88 bombers were heading in the general direction of Sheerness and Tilbury, and over the Kent countryside, quite a number of bombs were dropped indiscriminately indicating that a number of these Bf109s had taken to a new role of carrying bombs. But over various areas of mid Kent, heavy air combat actions began to take place.
17 Squadron, 73 Squadron and 253 Squadron, the all Hurricane squadrons from Debden were vectored to the Hendon and Northolt area. Orders were to patrol Hendon at 20,000 feet. Apparently no contact was made with the enemy, and only 73 Squadron reported that a visual sighting was made, but the enemy was flying at approximately 33.000 feet and did not appear to be escorting any bombers. The Debden controller instructed 73 Squadron not to increase height and stay at 20,000 in the patrol area. On arrival at base later, all squadrons reported that no contact was made with the enemy.
1530hrs: One of the combat areas was in the Dover area. Heavily involved was 41 Squadron Hornchurch who took on a large formation of Bf109s. Two of the 109s became sandwiched between 41 Squadron Spitfires and trailing smoke dived down to low levels in a bid to make good their escape. Both of these managed to return to Wissant without any further attack being made on them.
Over "Hells Corner" another Bf109 was to break away and attempted to return to its base after receiving damage, but the damage was too severe and it had to make a forced landing, but three other 109s were not so lucky. Two were shot down and crashed into the Channel, another was destroyed when it crashed near Deal, but not after the squadron sustained some bruising from the German fighters. At 1535hrs, F/O J.G. Boyle's Spitfire was hit by gunfire from a 109 over Manston, and had to return to Hornchurch. At 1540hrs, P/O J.N. Mackenzie's Spitfire was severely damaged and while the pilot was unhurt, it is believed that his aircraft was beyond repair after it crash landed. P/O H.H. Chalder was another who had to return to base while P/O H.C. Baker had to make a forced landing at Stelling Minnis after he took a hit while in combat over Manston.
1540hrs: The action here was with 501 Squadron Kenley who took on some Bf109s over Ashford. They were not as lucky as 41 Squadron as P/O Bennions describes their only success of the day:
501 Squadron was to lose two Hurricanes in this engagement. One of them was Sgt J.H. Lacey who managed to bale out of his stricken aircraft, while the other was Sgt E.J. Egan who went down with his Hurricane that had burst into flames. Both incidents occurred over Ashford.
19 Squadron also got into the action and over north Kent was credited with two destroyed Messerschmitts. As it turned out, both were shot down by Sub Lt "Tony" Blake, who as it happens turned out to be the Navy's highest scoring fighter pilot.
Evening: The usual raids began to commence at about 2000hrs. The first raids were on London where continuous waves of bombers pounded the city.
Later in the evening, Junkers Ju88s went on a bombing spree over Merseyside. Again, the bombing was either not accurate or the Germans just dropped their bombs anywhere as long as they were over the city. There were plenty of industrial and dock areas that could be bombed, but the residential areas were also taking a beating and again, many lives were lost. The cities of Newcastle and Durham were also hit, but many houses were damaged and destroyed. Reports of bombs landing in open country was again reported well away from towns and cities.
Victory came at 2345hrs to one of the Defiants of 141 Squadron converted to night fighter operations and based at Biggin Hill. A number of Junkers Ju88s were detected crossing the coast near Dover and 11 Group dispatched a flight from 141 Squadron. Interception was made north of Ashford and Sgt Lawrence and Sgt Chard began their attack on B3+OL. The badly damaged bomber finally crashed in a residential street in Maidstone killing all the aircrew.