Aces High serves to remind us that, if not an entirely scrupulous politician, nor a perfect husband, Alan Clark really was a superb military historian.

There has evolved something of a myth about the war in the air between 1914-1918. The myth goes that, while in the filth and gore of the trenches below any idealism and chivalry quickly sputtered and died, in the purer air above the last noble heroes battled in one-to-one dogfights like knights of old. It is a myth that Clark shoots down in flames, with characteristic iconoclasm.

One of the great RFC aces was Mick Mannock, famed for his encounter with a training instructor, out in a formation of six, with five of his very green-horned pupils. Mannock first shot down the instructor and then ruthlessly pursued each of the novices and shot them down one by one. This wasn't chivalry, it was war, and although more elegant to watch, it was every bit as lethal as Passchendaele.