[Peter Cornwell]

Nobody can suggest that there was ever a problem with the number of fighters available to Fighter Command - BEAVERBROOK had that well under control. But there were growing concerns over the wastage rate of fighter pilots and the inexperience and/or continuing endurance of those remaining on strength. DOWDING's policy of rotating squadrons between Groups also resulted in a similar diminishing quality (though to a lesser extent) within his reserve pilot pool. Pilot attrition within RAF Fighter Command was on a knife-edge. But the continuing availability of serviceable airfields in southern England was the other major factor which brought us so close to imminent defeat in early September 1940.