JB Seatrobe on the swashbuckling naval hero and 19th century radical who was expelled from Parliament following a Stock Exchange scandal

Admiral Thomas Cochrane was the inspiration for the naval heroes of authors such as Patrick O'Brian. He was also active in radical politics in the early 19th century, and sat in the Commons for 12 years.

A rising naval star, he first stood for Parliament at an 1806 by-election at Honiton, a notorious rotten borough. The radical journalist William Cobbett had planned to stand on an anti-corruption ticket. However, when Cochrane declared at the public hustings that he would never accept "place or pension", Cobbett stood aside in favour of this more viable candidate. Despite stories of his personal fortune, he refused to bribe the electors, even though one had told him that "I always votes for Mr Most!". Not surprisingly, the government candidate, who paid £5 per vote, was returned at the 17 June poll with 259 votes to Cochrane's 124.

However, Cochrane's squeaky-clean image was soon undermined. Having been beaten once by playing fair, he was determined to win Honiton in the imminent general election. He gave each elector 10 guineas as a reward for not succumbing to bribery at the by-election.

The Honiton electors expected a repetition of his generosity at the general election, but Cochrane, who was returned unopposed at the 31 October 1806 poll, did not pay any bribes, though he provided lavish hospitality to his supporters. Embarrassingly, he was hounded by creditors years later for the outstanding bill.

He never appeared in Parliament as Honiton's MP, spending most of that period at sea. At the 1807 general election, Cochrane knew that, if he wanted to campaign against naval abuses, he needed to do so from a more high-profile, less corrupt constituency. Westminster was ideal, as he said at a campaign meeting: "A man representing a rotten borough cannot feel himself of equal consequence in the House with one representing such a city as Westminster." He came a good second at the end of the poll on 23 May 1807, and was elected to one of Westminster's two seats.

He used his maiden speech on 26 June to stress his independence, but his regular attempts to initiate inquiries into abuses of patronage and into his other hobby-horse, naval abuses, were easily voted down. Later that year he was called back to active service for 18 months.

He returned to the House in 1809 an even greater hero. This time he became embroiled in personalised naval disputes as well as other controversial questions, such as blatant inequities in state payments and pensions. In one speech, he compared public payments to the Duke of Wellington's family as being "equal to 426 pairs of lieutenant's legs".

He survived a serious attempt by some of his erstwhile constituency supporters to replace him at the 1812 general election, by appealing directly to the electors through a personal manifesto. At the 8 October poll, he was returned unopposed for Westminster. In 1814, Cochrane became embroiled in a Stock Exchange scandal. Whatever the truth of his involvement, the government seized the opportunity to destroy an irritating opponent. He was put on trial, convicted and sentenced to a year in jail, a £1,000 fine and one hour in the pillory. He was also stripped of his naval offices and public honours.

The final disgrace was his expulsion from the Commons. Cochrane appeared in the House to defend himself on 5 duly, but made an intemperate speech denouncing his trial judge and jury. He was expelled by a vote of 140-44, though his loyal Westminster electors returned him unopposed at the subsequent by-election on 16 July.

A bizarre postscript came with his escape from jail the following March, and his sudden reappearance at Westminster. Cochrane thought his status as an MP made his imprisonment invalid, but clerks would not allow him to participate until he took the oath, which required formal delivery of his certificate of re-election. While awaiting its arrival, he was arrested in the House and sent back to jail. He did not resume his parliamentary career until his release that July.

By the 1818 general election, Cochrane had no wish to remain in the Commons. He made his valedictory speech on 2 June 1818 during a debate on parliamentary reform. Saying that it was "probably the last time I shall ever have the honour of addressing the House on any subject", he denounced the current repressions and warned that, if the House does not reform itself from within, "it will be reformed with a vengeance from without".

He resumed his dashing naval career, serving privately in independence wars in South America and Greece, and with the Royal Navy in the West Indies. Gradually, he was publicly rehabilitated, with his ranks and honours restored, though, wisely, he never sought a return to the Commons.

Next month: CP Scott