Churchill was asking about operational units being held in reserve, not aircraft held in reserve, and when Park said "none" he was only referring to units within 11 Group, not the whole of Fighter Command. In other groups a number of Squadrons saw no action at all on this day.
Thinking about this, again my books are at home so is from memory. The operational situation of 11 group was at the front line of the defence. It was part of the strategy that when 11 group was committed then adjacent groups would share the load as I remember 10 group did their job but 12 group was somewhat "remis" with Leigh Mallory's politiking. For 11 group to be completely committed with no reserves would be expected when the whole of the Luftwaffe was going between the Pas de Calais and London. Also as I remember Uxbridge was a short detour from Churchills normal trip from Chartwell to London, I believe he was there on many occasions although how much he knew of the minutae of Dowding and Parks strategy I dont know
Last edited: