Interestingly, the German Navy, Army and Air Force each had their own plans and ideas as to how and where the invasion should be launched. There seems to have been little co-operation between the German armed forces, and despite the impressive build up of barges and other equipment in the Channel ports, the actual detailed planning for the operation, code-named "Sea Lion", was never really thrashed out. All depended on the success of the Luftwaffe it would appear, before the invasion was to be taken seriously.

Starting on 10 July 1940, the Luftwaffe attacked shipping convoys in the Channel and Channel Ports. They also suspected the importance of the British radar masts and attacked the stations on the South coast, damaging some of them very badly.

One of the aircraft types used in these raids was the Junkers Ju87 'Stuka' dive-bomber. These were very accurate, and had been particularly successful earlier in the war when there was no effective fighter opposition. But when dive-bombing, they were very vulnerable to attacks against them and the Hurricanes and Spitfires of Fighter Command found them easy prey. Because of their heavy losses, they were withdrawn from the battle in mid-August.

In this stage of the battle, the Luftwaffe was in effect probing the British defences - looking for weaknesses before a major assault could be launched to exploit them.

Phase2

At the beginning of August, with German invasion forces and troop barges being assembled on the French coast, the raids against the South coast of England were increased in size and number.

Believing that the British early warning system had been destroyed and the coastal towns sufficiently 'softened up' for an invasion, the Luftwaffe began the next stage of their plan.

On 13 August (called Adlertag or Eagle Day by the German High Command), massive raids began on the airfields of 11 Group. The aim was to destroy the RAF, either in the air or on the ground, in South East England. To put pressure on the British defences, the Germans sent high and low level raids to different targets at the same time.

Sometimes low level raids sneaked past the battered but still working radar stations, and the first warning the British fighter pilots had was bombs landing on their airfield. Particularly good in the low-level role was the Dornier Do 17 and its derivatives, several of their raids succeeded in achieving complete surprise and escaping any form of interception.

This pattern continued into September and the situation in 11 Group became desperate. Small civilian airfields were used in the emergency, as many RAF stations became badly damaged. The Spitfire and Hurricane could easily take off from grass fields, but the maintenance and spares supply situation became dangerously stretched. Ground crews working in the open suffered heavy casualties from the raids, and many maintenance facilities were destroyed in the bombing. Despite this, the crews kept the fighters as combat ready as possible, winning the Battle on the ground as the pilots were in the air.

Suggestions were made that the fighters should be pulled back north of the Thames, but Dowding and Park knew that this was exactly what the Germans wanted, effectively giving them air superiority over the intended invasion area. So the 11 Group squadrons stayed and fought for their lives.

To keep up the pressure, the Germans began night raids, to stop the defenders repairing damage overnight. On one night raid, some aircraft bombed civilian areas of London by mistake; a mistake which was to become a crucial turning point in the Battle. Attacks on civilian centres were something which had been specifically banned by Hitler, who was still hoping at this time that the hopelessness of the situation would cause the British to sue for a negotiated peace. The German High Command knew that widespread civilian casualties would only harden the resolve of the nation to fight on. In reply to this accidental attack, the British bombed Berlin. Fears grew that cities would be raided more often, so children were evacuated again in a second mass exodus to places of safety in the country, as they had been during the Phoney War of 1939.

However, just when it seemed that the country and 11 Group in particular couldn't continue for another day, the Germans changed their tactics.

The change of plan was a mistake for a number of reasons. It gave 11 Group a chance to repair their airfields and radar sites, so the defences became fully operational again. The German Me 109 fighter could only carry enough fuel for 20 minutes flight over Britain, so London was on the edge of its limited range. Finally, the German raids now came within the range of 12 Group, and their large formation tactics known as "Big Wings".

Much has been written about the different tactics employed by Nos 11 and 12 Groups and their commanders, and the supposed disagreements these differences caused. Suffice to say that 11 Group's fast response tactics with whatever was available, meeting the enemy formations as far from their targets as possible, was best suited to their geographical proximity to the German bases. 11 Group Squadrons simply did not have the time to assemble, they had to get airborne and climb to height as quickly as possible or miss intercepting the raid altogether. 12 Group, being further north had somewhat more time for a large formation of fighters to assemble and climb to meet the oncoming attacks, tactics that suited their circumstances. Dowding, as befits a true leader, allowed his Group commanders to run their organisations as they saw fit, the detail work being done a Group level while he dealt with the overall picture. The life of an 11 Group pilot was made more difficult by these operating methods, but Park understood the true situation of his command, and employed his Squadrons with brilliant effectiveness. In the light of the outcome of the Battle, and the fact that for many days he had the fate of a nation resting on his shoulders alone, Park must be considered as the architect of the RAF's victory.

Knowing the target to be London and the industrial centres, the British controllers now had time to assemble a large number of fighters to attack the German formations and break them up before they could bomb. The appearance of large numbers of Hurricanes and Spitfires came as something as a shock to the Luftwaffe pilots, who had been told by their intelligence officers that Fighter Command had practically been wiped out by the earlier raids against the airfields. By changing tactics and targets, the Germans had actually helped Fighter Command to deal with raids.

For the people living in the cities, the Blitz had begun, as night raids followed daytime raids and gave the civilians little rest. Everybody was in the front line, and there was little the RAF could do to stop the night raids. Airborne radar was in its infancy, but there were some successes for the Blenheim, Defiant and early Beaufighter night-fighter Squadrons. Some of the Hurricane and Spitfire day-fighter Squadrons also took part in the night defences, but relied largely on luck to make an interception.

The German raids continued, but the RAF had started to develop night fighters equipped with radar which could tackle the problem. The first AI (Airborne Intercept) radar sets were being fitted to Blenheim, Defiant and Beaufighter aircraft, and proved increasingly effective as the equipment developed and operational experience increased.

During the day, German fighters, mostly Me 109s but occasionally Me 110s, were sent over carrying bombs in small and large scale Jagd-bomber or "Jabo" raids. Largely these nuisance raiders were aimed at engaging the RAF fighters and disrupting defensive operations over the South-East. Defenders, tired from the night attacks, were stretched still further by these raids. They flew fast and high and were difficult to intercept. The radar warning was not long enough to allow a Spitfire to climb to this height from the ground, so the RAF had regular patrols between 15,000 and 20,000 feet. This was a costly and inefficient use of the aircraft and pilots, exactly the situation the control system had helped to avoid during the earlier phases of the Battle, but German losses began to increase. The weather also began to worsen and the raids stopped in late October.