Holmes's passion for the history of conflict was fired during his last year at school when he was transfixed by the BBC series The Great War, shown in 26 parts in 1964. "I was hooked from the start," he recalled. "It was the first time I had seen early film slowed down so that men and horses did not walk with a jerky quickstep. And although I was about to go to Cambridge to read History and thought myself no end of a scholar, it was the first time I had seen it suggested that the war's generals might be anything other than mindless and inarticulate butchers."