`Where is the RAF?' was the oft-quoted question asked by soldiers waiting on the beach at Dunkirk, to where they had retreated following the German blitzkrieg through northern France, and where they were now being pounded by the Luftwaffe.

The air forces were there, as Norman Franks proves, detailing the outstanding achievements of the Allied pilots who fought, using outmoded tactics, against enemy pilots who had earlier had easy victories over the Polish, Dutch and Belgian air forces.

The RAF's achievement reminds us just how close Britain came to disaster in June 1940.