The Battle of Britain Five Months That Changed History, May—October 1940 by James Holland (z-lib.org).epub

enemies who would later come back and haunt him. Yet by May 1940 he
had believed Fighter Command was almost ready. Almost.
Now, though, it seemed as though everything that he had worked for
was being frittered away. Despite the efficiency of his early-warning
system, despite all the many changes he had implemented, the most
important ingredient of all was aircraft and trained pilots, and these were
being squandered uselessly over the battlefields of northern France and the
Low Countries. Unless this stopped, and stopped soon, and unless
something could be done to radically improve the rate of aircraft
production, the hard-fought-for development of Britain’s air defences would
have been for nothing. For in an all-out clash with the Luftwaffe now, RAF
Fighter Command would lose.