[Peter Cornwell]

Thank you for your comments. I have no wish to extend the life of this thread nor broaden its scope beyond addressing the original point raised by taitbb as challenged by mars.

Fighter Command squadrons held in immediate reserve were mainly based in adjoining Groups as you say. But many of these units had already been rotated in and out of the main battle area in No.11 Group over preceding weeks, until casualties prompted their withdrawal, and this movement inevitably created a cumulative debilitating effect on the fighting efficiency of Fighter Command as a whole. It is not simply a question of the number of pilots available at any point in time, it is also their relative experience & combat readiness. This qualitative factor, difficult to measure with any accuracy, was a source of growing concern amongst RAF Commanders. So, while they had not yet exhausted their reserve of pilots in terms of numbers, they were only too well aware, just how thin this finite resource was stretched. By the start of the critical two-week phase of the BoB commencing 24 August 1940 at least one in three of all No.11 Group pilots was deemed ‘inexperienced’ and even the balance included many pilots still relatively fresh from OTUs with little or no combat experience. Adoption of the ‘Stabilisation Scheme’ reluctantly effected by DOWDING on 8 September 1940 is ‘best proof of the seriousness which the outlook was viewed at HQ Fighter Command’. Furthermore, the strength of Category A squadrons was to be maintained by intakes from Category C squadrons - officially ‘considered unfit to meet German fighters’. (Cf. Chapters XIII & XV of the official history The Defence of the United Kingdom by Basil Collier: HMSO 1957). This would inevitably result in even further dilution in the quality of the British air defences. Fighter Command was on its knees, the Germans had the advantage, but they failed to exploit it by prematurely switching the main thrust of their attacks away from RAF airfields to London. These are well-documented and long-established facts as mentioned by taitbb in post #6.