The sea-dog who inspired a literary genre

Cochrane: the life and exploits of a fighting captain by Robert Harvey (Constable, £16.99)

Truth can be not only stranger but a lot less just than fiction. If you thought that the novelist Patrick O'Brian was frequently harsh to the point of sadism to his all-English sea-dog hero Jack Aubrey, just wait until you read the true story of Aubrey's model: Thomas Cochrane (1776-1860), 10th Earl of Dundonald.

Truth can be not only stranger but a lot less just than fiction. If you thought that the novelist Patrick O'Brian was frequently harsh to the point of sadism to his all-English sea-dog hero Jack Aubrey, just wait until you read the true story of Aubrey's model: Thomas Cochrane (1776-1860), 10th Earl of Dundonald.

For all his setbacks, Aubrey was promoted through the ranks of the British Navy at reasonably frequent intervals. The thoroughly independent-minded Cochrane got no further than captain before he was accused of a bizarre Stock Exchange fiddle, stripped of his Order of the Bath and sentenced to prison and the pillory. Nor did Cochrane have a loyal friend like Aubrey's Stephen Maturin, whose diplomacy and influence are so often the saving of the bluff, tactless Jack.

It took the Chileans, the Brazilians and the Greeks to give Cochrane high naval commands. Only in his old age did he become a prophet with official honours in his own country. Napoleon repeatedly commented on the idiocy of the British in not making good use of their best commander since Nelson.

What Cochrane always had, however, was a huge popular following. The people loved his dash and audacity. He took Nelson's adage "Never mind tactics, just go at 'em" to its extreme. In his first command, the 14-gun brig Speedy, he harassed merchantmen on the Spanish coast so effectively that traps were set especially for him.

In 1801, while chasing a gunboat through a fishing fleet, he found behind it the 32-gun Gamo, a frigate four times the size of his, with 319 men to his crew of 54. Too close to cut and run, and not a man to consider surrender, he sailed straight towards her, raised the American flag to confuse and gain time, then nipped around on to her lee. There, her guns could fire only over his ship. He locked his spars into hers and began to pile broadsides into her hull. It was luck that the Spanish captain died in the first broadside, but brilliant management to take the Gamo and sail her away as a prize.

Besides possessing a genius for the unexpected, Cochrane was formidably competent. He trained his crews to peak efficiency, and they would have followed him to hell and back - not least because he rarely lost a man and did his best to get them prize money.

One of the most evocative illustrations in Robert Harvey's wonderfully readable book is an 1804 poster. Headed "Doubloons" and "Spanish Dollar Bag", it invites "seamen and stout hands" to serve with Cochrane on "The Flying Pallas of 36 Guns", a "new and uncommonly fine frigate".

The capitals appeal to the sporting of temperament: "My LADS, The rest of the GALLEONS with the TREASURE from LA PLATA are... to sail for PORTEVELO. They stay a few days only... Such a Chance may never occur again... Captain Lord Cochrane (who was not drowned on the ARAB as reported) commands her. The sooner you are on board the better."

Cochrane's star-crossed naval career was far from his only claim to fame. In politics, he took on just as audacious odds. Although blue of blood, he chose to run as a Radical MP for Westminster, one of the few boroughs where electors had freedom to vote. With William Cobbett and a handful of other MPs, he stung the complacent sides of the corrupt Whigs and Tories to such an extent that there is little doubt, in Harvey's mind at least, that he was set up as scapegoat in the Stock Exchange fiddle.

Cochrane was also an ingenious inventor. He experimented with coal-gas lighting and all manner of nautical improvements. He built the first steam warships and helped out Brunel with the engineering problems of tunnelling under the Thames.

This is not the first biography of Cochrane and probably won't be the last. But his story deserves retelling. Cochrane inspired not only O'Brian; CS Forester made use of incidents in his career, and Captain Marryat, once a midshipman under Cochrane, drew him to the life as Captain Savage in Peter Simple. As Robert Harvey convincingly argues, it is Cochrane's exploits that gave birth to the fictional genre of Napoleonic sea-adventures.