Dunkirk, one of the summer’s most hyped and star-strewn aspiring blockbusters, is about that iconic crossroads moment of the early Second World War: the attempted evacuation in 1940 of nearly half a million British, French and Belgian soldiers from the titular French beach. Cut off from air support, surrounded by the German army, bombed to breaking point by the Luftwaffe – and with the safe haven of Dover less than thirty miles away – the Allies face catastrophe. A desperate evacuation strategy is mounted over land, sea and air that enlists not only the Allied forces but also British civilians…