In the midst of its global struggle with Napoleonic France, Britain lost three imperial heroes within months of one another. Nelson’s death at Trafalgar on October 21 1805 was followed in January 1806 by that of Prime Minster William Pitt the Younger, “the saviour of Europe”, who, exhausted by work and port, died at the age of just 46. The third in this triumvirate, Charles, First Marquis of Cornwallis, had predeceased both, drawing his last breath aged 66, 16 days before Trafalgar, while serving a second term as governor general of Bengal.

That all three had achieved greatness was orthodoxy at the time of their passing. Today, Nelson, certainly, and to some extent Pitt are established among the canon of British heroes, but Cornwallis is now a neglected when not disparaged figure. Though he saw action, both military and administrative, in India, across mainland Europe, and in troubled Ireland, he is perhaps best remembered now for his disastrous military ventures in the American War of Independence.

Strangely, Cornwallis was exonerated at the time for his failures in the Americas, not least the catastrophic defeat at Yorktown in October 1781: traditionally it was George III and his advisers who got it in the neck. Yet the tone of Cornwallis’s time in the Americas had been set four years before, in Trenton, New Jersey, where he had George Washington and his rebel army trapped in a seemingly hopeless position. Cornwallis, with prevarication and caution stamped through his spine like Blackpool rock, left the enemy to stew during the night. In sub-Wodehousian language, he announced his intention to “bag the fox” in the morning, by which time the vulpine Washington – who was in another league as a strategist and tactician – had fled to fight another day. The consequences were profound.

Richard Middleton, in this defensive biography of Cornwallis, the first for almost half a century, proves himself an able historian who has mastered the relevant sources, but his is a thankless task. It would take a Gibbon to bring this earnest, clunking, naïve but essentially virtuous man to life, despite the colourful boards he trod.

Middleton argues that Cornwallis’s peripatetic career was born of tragedy. In 1768, aged 29, he had married Jemima Jones, a woman of poise and elegance, though of no particular social prominence – he, by contrast, was born in Grosvenor Square and educated at Eton and Cambridge. It was a love match, which produced two children, but Jemima died on Cornwallis’s return from the Americas, in February 1779: “Like many others suffering bereavement,” he looked to travel to alleviate his suffering.