If Simon Mann did not exist, you would have to make him up. A classic English adventurer with a textbook establishment start: Eton, Sandhurst, the Scots Guards. The son of a wealthy and sporting father, a one-time captain of the English cricket team who made his fortune in brewing. A restless soul as at home in a Pall Mall club as on the streets of Belfast.

Off the top of my head, I can think of half a dozen friends with backgrounds almost exactly like his. But this morning, as they commute to their investment banks, or sit down in their libraries to write, Mann is the one who will stand up in manacles, his hair thick with lice and his body lean from hunger, to argue before an African court for his life.

Mann’s story is an old-fashioned tale of greed and adventure, a story peopled by improbable characters from the allegedly cannibal dictator and his tyrannical new best friend; from the shady son of a British prime minister to the armed men who shift about Africa fighting other people’s wars.

It started conventionally enough with enrolment at Eton, where Mann acquired the casual confidence of entitlement. From there, he joined the Scots Guards, Britain’s most pukka regiment, and underwent officer training at Sandhurst. It was once a common career path for many future businessmen or diplomats, but Mann had no intention of moving behind a desk. He signed up for the SAS, passing the gruelling selection process on his first try.

Mann served as a captain in Cyprus, Northern Ireland, Germany, Norway, Canada and Belize before leaving military life in search of more adventure and better pay. From then on, his life departed from the regimented and predictable. He set up a company selling hacker-proofed software but was quickly drawn back to security, providing wealthy Arabs with guards for their Scottish shooting estates. Mann was tempted briefly back into uniform during the first Gulf War as an aide to Sir Peter de la Billiere, the head of British forces.

It was on his return from the war that he met his third and current wife, Amanda. Mann already had three children and had undergone a vasectomy, but meeting Amanda persuaded him to have it reversed. She was four months pregnant with their first child when they were married at Chelsea register office in 1995.

In the meantime, Mann had moved full-time into the world of mercenaries, setting up Executive Outcomes to make millions protecting Western oil interests during Angola’s brutal civil war. When that company’s reputation grew too murky, he set up another, Sandline, with a fellow former Scots Guard Lieutenant Colonel Tim Spicer. The company famously defended its arms supplies to Sierra Leone, in contravention of a United Nations embargo, claiming they had the British Government’s knowledge and approval.

Still it had been a close call. Mann hung up his boots, for a time at least, buying a house in the exclusive Cape Town suburb of Constantia, where his neighbours included Mark Thatcher and Earl Spencer. Thatcher began a good friend, and Mann and his family spent Christmas with him and the newly widowed Baroness Thatcher. Mann’s life of fishing, beaches and cocktail parties convinced many friends that he had now retired – until his shock arrest at Harare airport in 2004.

Mann had gone to rendezvous there with 66 South African former soldiers who had just landed in a Boeing 727 owned by his company. What emerged later was straight out of the plot of Frederick Forsyth’s Dogs of War. In it, a British businessman hires mercenaries to overthrow the government of newly oil-rich Equatorial Guinea. Mann, it was alleged, was the real life gun for hire.

Mann was said to have taken on the job in return for cash and a future stake in the country’s oil reserves. Robert Mugabe, the leader who now had him in jail, also needed oil. Guinea’s president, Teodor Obiang Nguema, smelled a win-win solution in the offing, and promptly offered Mr Mugabe oil in return for a questionably legal pre-dawn extradition from Zimbabwe.

Criminal or thrill seeker? Paul Greengrass the director who once worked with Mann, said of him: “He is a humane man, but an adventurer. He is very English, a romantic, tremendously good company.” Humane is not a word often used of President Obiang, who presides over one of the worst human rights records in Africa. Mann is a man who belongs to a different era, when white buccaneers believed they ruled Africa and did what they liked there. Nobody told him that era was over.

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