The bicentenary of Trafalgar has allowed authors, documentary-makers and journalists to dive back headlong into the colourful world of George III’s navy: rum, sodomy and the lash all right, but also the excitement of the pursuit of the French fleet to the point of its effective destruction at the battle itself, off Spain, on 21 October 1805. Yet this superb book by Roger Knight – a professional maritime historian whose achievement in this study of Nelson will now make it the definitive life – prompts a more important reflection: upon the nature of heroism, not merely in an age very different from our own, but in any context at any time.

Knight’s book does not, of course, merely confine itself to such a consideration. As well as being a life of Nelson, it is also a pretty thorough compendium of life in the Navy and in the relevant political circles of the period. After a thirty-five-page introduction that, among other things,