This terrifying alternative reality is actually based on historical facts. The book follows the real course of events up to1 September, including the planning in Britain and Germany, and the aerial war. The fictional story then supposes that the Germans halted their advance in France along the Seine and the Aisne after the fall of Paris and that Marshal Petain conceded an armistice at that point. The Panzer divisions are thus able to rest and re-equip in northern France...A brilliant blend of meticulous research and imagination, this book is bound to appeal to anyone with an interest in the causes and effects of historical events, and indeed to anyone interested in world war history itself.

It's the summer of 1940 and the Nazis have crossed the English Channel to invade Britain. They advance North from the South coast and great swathes of Southern England come under German control. Fiction, of course, but an invasion of Britain was planned by Hitler to take place in the summer of 1940 - how far would the Germans have been able to advance? Would they have been successful?