[Nick Beale]

First off, if you are to cite the percentage of 2 TAF losses which were Typhoons then you need also to say what percentage of 2 TAF assets the type represented. It would also help to break down the losses by cause (and ditto for the tac support Spitfires). Similarly, if you're going to use a term like "unsustainable" then this needs to be set against the projected supply of replacement aircraft and pilots and the expected duration of the war.

Britain's manpower shortages were becoming apparent in Normandy (D'Este discusses this at some length but could not find answers on some crucial points re reserves in the UK). I believe that British divisions were being amalgamated and disbanded from Summer 1944 onward and certainly RAF Squadrons ditto in early 1945 (but this didn't seem to preclude the rotation of 2 TAF units to Armament Practice Camps in the UK) but as you say, German-held territory was shrinking fast by then.

There is another issue of context: the acceptability of losses will vary according to a commander's perception of what those losses are buying. (This board has seen a heated debate in the past about how Luftwaffe losses in France in 1940 exceeded those in the Battle of Britain. But in the former case much France was conquered and the country put out of the war - Germany's objectives were achieved in other words. In the latter, the Germans lost a lot of men and aircraft and came away with what?)

I feel that you fixate on direct destruction and morale effects while overlooking the disruption and paralysis produced by air attack or, yes, the fear of it. The less freely an army and (crucially) its supplies can move, the greater its disadvantage against an enemy not likewise handicapped. That is surely something more than your "negligible damage to the German war effort." Strategically, the same holds true for goods and materials in an industrial economy. Germany's "underground factories" (most of which were probably some component sub-contractor in an old tunnel) may have produced the goods but there is ample evidence of the difficulty of distributing them or of bringing sub-assemblies together into a finished product, or getting one vital bit for (say) an aircraft when the transport links were smashed or under interdiction by those "defeated" Typhoons, Spitfires, P-47s and P-51s.

And the material you have cited does not, to my eyes, amount to any kind of "admission of defeat" by Flak. It does however look like a recognition that German Flak was exacting a cost which cold not be justified by the results being obtained from some specific types of employment of close support aircraft. And the literature has often mentioned the Allied Generals' concerns that their troops were becoming hooked on air support and wouldn't make a move without it.

You speak of "Flak, which was becoming increasingly concentrated as German territory shrank and supply lines to the Ruhr factories diminished." Were not German guns often abandoned owing to lack of vehicles to move them and fuel to move the vehicles? Did ammunition and spare parts not have to brought to where they were needed? Did the raw materials to make them not have to reach the factories? Any "advantage" secured by the events leading up to the encirclement of the Ruhr was in reality a last gasp, dangerous for those who had finally to stifle it but not "sustainable."

21 Army Group's performance has been extensively debated (D'Este again or Max Hastings) and the reasons advanced for its perceived shortcomings are numerous but the British national resolve to have no more Sommes or Passchendaeles seems to be high on the list, alongside Montgomery's methodical approach and painstaking preparation.