Quite right Crashdive wrt to the Lancasters and their crews.However the fate of the war had already been decided by then.
In 1940, Britain stood alone, with the only thing preventing Operation Sealion (the invasion)was this Thin Blue Line, The Narrow Margin.
America had not yet entered the war, and Russia had still to be invaded.
Defeat was on the cards, a real possibility.
The country was, quite simply, fighting for it's survival.