The Chronology: Page-45
It now appeared that the Royal Air Force were starting to gain the upper hand, but even though London suffered serious damage and hundreds of casualties from September 7th onwards, the battle was far from being over, although the turning point could be said, happened on September 15th. Adolf Hitler may have postponed the invasion once again, but the intensity of day and especially night raids were about to increase.
Göring was under instructions to continue bombing attacks on the British capital although personally, he would have like to revert back to destroying the fighters, the airfields and ground
support installations of the RAF, but unlike the British chain of command, he was under instructions from Hitler personally. Daytime attacks would still continue, and by increasing Bf109 and Bf110 escort duties to the
bombers, he could hopefully destroy at least some of Fighter Command by forcing them to send fighters into the air, but with instructions to concentrate on the industrial areas of London's East
End and bombing London itself, it was going to be a big ask if the targets were not the fighter aerodromes themselves. Night time bombing would continue, and this was to become more widespread with greater intensity and with more high explosive bombs followed by thousands of incendiary bombs.
The flying of squadrons in pairs was
more of a compromise on the part of Park who refused to send up the number
of squadrons as Douglas Bader and Leigh-Mallory had wanted, although it
must be admitted that Bader's "Big Wing" was destroying large numbers of
enemy aircraft when given the opportunity. The combination of the "Big
Wing" and other squadrons flying in pairs proved how successful the method
was during the British victory on September 15th. We were not to see the
last of paired squadrons yet.
WEDNESDAY SEPTEMBER 18th 1940
Conditions were expected to be a continuation of the previous day except that the low to medium cloud that brought the rain periods would disappear. The day was expected to be bright and clear although the squally winds would continue.
0900hrs: Radar stations from Pevensey to Foreness detect a formation building up just off the Channel coast at Calais. The information is passed on to FCHQ immediately.
0920hrs: Keith Park was ready to issue orders to his station commanders after a meeting with Hugh Dowding the previous day. But the news of another detection allowed him to delay the new instructions. The Observer Corps reported tiny specks at high altitude which indicated that it was a formation of fighters flying at heights in the region of 20,000 feet between Folkestone and North Foreland.
At varying intervals, a total of fifteen squadrons of Fighter Command were scrambled to intercept.
0940hrs: The enemy fighters reach Maidstone and decide to break up into two separate formations. One headed towards Sheerness while the other veered north towards the open waters of the Thames Estuary. Only six of the fifteen Fighter Command squadrons make contact between Maidstone and Chatham. These were 17 Squadron Debden (Hurricanes), 46 Squadron Stapleford (Hurricanes), 73 Squadron Debden (Hurricanes), 257 Squadron Debden (Hurricanes), 501 Squadron Kenley (Hurricanes) and 603 Squadron Hornchurch (Spitfires). Most of these squadrons, once they observed that the enemy was all Bf109 fighters, made their presence felt but broke off any form of attack in accordance with Parks instructions not to be drawn into combat with German fighters unless they were escorting their bombers.
A couple of flights from both 501 Squadron and 603 Squadron did become involved in combat after being jumped by Bf109s. One pilot baled out of his Hurricane over Staplehurst while Spitfire pilot of 603 Squadron was killed after his aircraft was shot up and crashed near Ashford.
1000hrs: No sooner had a number of the squadrons landed that others were scrambled and vectored to intercept enemy formations detected over Dover and over the Thames Estuary. Some of the squadrons that were scrambled earlier were vectored to new locations while more squadrons were released.
Keith Park back at Uxbridge, watched his large map table below as squadrons moved into position. These had been carefully despatched from various airfields to be vectored to intercepting positions. He takes the opportunity in contacting his station commanders with instructions regarding any invasion attempt of Britain. His own fighters were to give protection to naval forces and their bases and also to provide cover for Bomber and Coastal Command operations. They are to distract enemy dive bombers from attack on ships that are engaging enemy vessels and destroy enemy aircraft carrying troops or tanks. They would attack the barges and landing craft and protect British troops from dive bombers. RAF personnel would combine with the Army and jointly defend forward aerodromes. Demolition of installations and withdrawal would take place only as a last resort, pending the arrival of Army mobile forces. Other instructions were; inland aerodromes must not be evacuated and were to be held at all costs, Group control would be maintained as long as sector operation rooms were still intact and telephone links to and from them was still possible. In the event that group control became impossible, then the sector commanders would take charge, and if the sector control failed, then it would be up to senior officers to act on their own initiative. He emphasized that an invasion would be defeated in seventy two hours at the most, and that both pilots and ground crews would expect a 'hard time'. 
A number of the squadrons engage the enemy over the Estuary and a number of individual combat actions take place at various locations at the mouth of the River Thames. 1(RCAF) Squadron Northolt (Hurricanes) becomes involved and has one of its fighters shot down, but P/O E.W.B. Beardmore bales out and receives slight injuries. 66 Squadron Gravesend (Spitfires) engage Bf109s over North Kent and one of the Spitfires is hit and the pilot, Sgt D.F. Corfe sustains injuries after he managed to crash land the aircraft at Perham. 72 Squadron Biggin Hill (Spitfires) manage to turn a formation of Bf109s around while over Sheerness and continue the chase as the enemy fighters head towards Dover and the Channel. Three Spitfires are damaged with two of their pilots receiving injuries while the third in unhurt.
1200hrs: The first German bombing raid is detected coming in north of Dover. It consists of about 70 Junkers Ju88s escorted by 100 Bf109 fighters. Fighter Command despatches another twelve squadrons who engage, but not before many bombs fall on the dockyards and surrounding areas of Chatham. Many of the bombers scatter going in all different directions, but it is estimated that 60 manage to get though and head towards London. Most bombs fall on the central area of the city, but within forty minutes most of the bombers are heading back towards the coast.
More contacts were made by the south coast radar stations. Again the
German forming up position was again over Calais, where two separate formations
were detected. Early sightings indicated that there were between one hundred
and one hundred and fifty aircraft heading towards the English coast and
the Observer Corps reported that they were crossing the coastline between
Dungeness and Folkestone and towards Ashford and Chatham. This time, it
was reported that there were no sign of fighter escorts, and that the formation
was made up of mainly Do17 and Ju88 bombers.
By now, a number of squadrons had engaged the enemy over the north Kent
coast with many squadrons that had left aerodromes in the protective area
around London. Park again called on 12 Group and in response Woodhall scrambled
the 'Duxford Wing' to patrol the area from London to Gravesend. Bader decided
that it would be best to keep below the cloud layer of 24,000 feet and
stepped his squadrons at altitudes between 18,000 and 20,000 feet.
The 'Big Wing' continued its success in the combat. Against the white of the cloud base the enemy bombers stood out almost beckoning to be picked out one by one. The sky was a kaleidoscope of frantically weaving bombers and marauding fighters leaving trails in the air of criss-crossing vapour trails. One by one the bombers went down in flames and by 1730hrs the action was still continuing to the south of London.
Debden who earlier had released three of its squadrons towards the combat area failed to make contact with the enemy.
Evening: By 1800 hrs many civilians were making the most of the period that was the noted evening meal time in London and other main cities in Britain, before the now routine trek down to their Anderson shelters for evening protection. Others close to larger shelters and Underground stations also made the nightly haul to places where they believed would render them safe.
By 1930hrs, the first of the bombers came over and the first of the raids began. London was again hit bad and many buildings which had just their fires extinguished where hit again and it started all over. As one formation arrived, dropped its bombload, another formation was approaching lining up in the queue to add further destruction as the other formation left. Other targets were Liverpool and Manchester where the Merseyside docks received some heavy attacks. Although other bombs were dropped in various areas of Kent, Surrey, Hertfordshire and Middlesex, it is believed that they were bombs from aircraft dropped at random to lighten the load for the return journey.
 Len Deighton
Battle of Britain Jonathan Cape 1980 p186