THE STAGE IS SET

WHEN FRANCE, overrun in some six weeks by the full weight of the German forces, finally capitulated on 25 June 1940, Winston Churchill had already foreseen the next stage in world events. On 18 June, in an address to the House of Commons, he said, ‘What General Weygand called the Battle of France is over. I expect that the Battle of Britain is about to begin.’

Although an invasion of Great Britain had been considered by the German Naval Staff as early asthe late autumn of 1939, Hitler had not been approached with the idea until the last day of May 1940, when the collapse of France and the subsequent occupation of the Franco-Belgian coastline appeared imminent. Nor did Hitler become patently interested in the idea until 2 July, when he first gave orders for the three Services to initiate preparations for such an undertaking, and further stipulated the achievement of air superiority as an indispensable condition. A fortnight later Hitler had decided that preparations for a landing between Ramsgate and the Isle of Wight were to be completed by the middle of August. On 31 July he approved 15 September as the earliest D-day but reserved his final decision pending the results of the projected intensified air operations.

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Had the Germans followed Dunkirk with a speedy invasion of Britain, there was little organised ground defence to stop them, for the British troops evacuated from the French beaches had been forced to abandon all but their rifles. But an immediate invasion was not possible, for the German Navy, faced with the problem of transporting some forty divisions, the number Hitler considered necessary for the assault, had first to assemble all the array of small ships, barges, tugs, and steamers necessary to transport an invading army across the Channel, equip them for their task, and then move them to the assembly ports. The ports themselves nearly all needed repair; in addition, sea routes had to be swept clear of mines and German mines laid as a precaution against interception by units of the Home Fleet. Finally the entire force had to be trained and co-ordinated for the task. But, equally important, the prerequisite for invasion was command of the air, for even if a bridgehead could be taken by weight of numbers, the problem of supplying an army ashore in a foreign land had to be solved. Thus the aim of the German strategy was so to weaken the British fighter defences that the Luftwaffe would be able to give adequate support to an invasion of the British Isles.

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The strength of Fighter Command when the issue was joined on 10 July was fifty-two operational squadrons, all but three of which had already been heavily engaged in the Continental fighting. This force was composed of twenty-two squadrons of Hurricanes, twenty of Spitfires, eight of Blenheims, and two of Defiants. It had always been assumed that any attack on Great page 5 Britain would be heaviest in the South-east, i.e., the area directly opposite Northern France, and accordingly the majority of the fighter squadrons were disposed there under the control of No. II Group, commanded by the New Zealand airman, Air Vice-Marshal K. R. Park.¹

Throughout the battle Air Vice-Marshal Park had some twenty-two squadrons under his control, though his effective fighting force was restricted to about twelve Hurricane and six Spitfire squadrons. The balance was made up of Blenheim squadrons not suitable for daylight interception. This meant that, assuming every squadron could put its full complement of aircraft into the air, the fighting strength available to him at any time was limited to about eighteen squadrons, or less than 220 aircraft–the normal squadron formation being twelve aircraft. The situation, then, was extremely grave, for against this small force the Germans had available in the West on 10 August a total strength of 1808 bombers and dive-bombers and 1223 single-engined and twin-engined fighter aircraft. It was true that unless the other three Groups composing Fighter Command were heavily engaged they could be called upon to replace tired and depleted squadrons in No. II Group—as indeed they were—but here the Germans had one outstanding advantage. They could mass a heavy attack in one sector, where only a proportion of the British fighter strength was available, and at the same time by threats to other parts effectively compel Fighter Command to keep considerable forces away from the main zone of attack. Thus it was vital that the defenders should have sufficient warning of an attack so that the fighter squadrons could be airborne on their patrol lines in time to make an interception. This warning was achieved by means of a series of coastal radar stations sited at intervals around much of England, Scotland, and Wales.

Herein lay the essence of Fighter Command's defensive strategy, for had the Group Commanders been compelled by the absence of early warning to man their patrol lines constantly, they would have found themselves as often as not at the disadvantage of having to make interceptions with fighters low in fuel. In addition pilots, engines, and maintenance crews would have been subjected to severe strain by the long hours of wasteful flying. Over land the early type of radar was not effective and raid intelligence was supplied by a chain of Observer Corps posts whose members tracked enemy formations by sight or sound and reported the information to Fighter Command Headquarters.

This system, working progressively downwards from Fighter Command through the Groups to the Sectors, enabled the Command to identify approaching formations and allot the interception of raids to particular Groups, also to reinforce one Group by another if necessary. The Group Commander decided which Sector would meet each specific raid and detailed the strength in squadrons to be used. The Sector Commander decided which fighter units were to be employed and operated the machinery of interception by using the position, course, height, and speed of the enemy aircraft and of his own fighters, which were concurrently displayed on his plotting table in the operations room. He controlled his fighters by a series of courses broadcast over the radio telephone until, on making interception, tactical control passed to the fighter leader in the air who then directed his pilots into battle.

This was the system under which the battle was fought. Dependent on painstaking attention to detail by hundreds of men and women, it had been organised by Air Chief Marshal Sir Hugh Dowding in the pre-war years, and because of its inherent quality and flexibility it enabled the German mass attacks to be beaten.

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