Simon Mann will receive a lengthy prison sentence this week for plotting to overthrow President Obiang of Equatorial Guinea. But there is a growing belief in the capital Malabo that whether he gets the 32 years demanded by the prosecution, or the 10 years sought by the defence, he will soon be back in Britain, pardoned by the man he sought to oust.

“He will be pardoned within a year, two at the most,” said a lawyer, adding that last week’s five-day trial was a “charade”. Mann had said what Equatorial Guinea’s regime wanted him to say. “They negotiated [a deal] with Mr Mann.”

Diplomatic sources broadly concurred, though they thought Mann may have to serve three or four years before being repatriated, perhaps on medical grounds.

It was reported last night that Scotland Yard was investigating the attempted coup, and was considering sending officers to interview Mann. Scotland Yard refused to comment.

Mann, 55, is clearly enjoying privileged treatment in Black Beach prison, notorious for abusing its prisoners. He has his own cell, an exercise machine, books and magazines, and makes regular calls home. He lunches most days with Manuel Nguema Mba, the Minister of Security. They eat food and wine delivered to the prison by the Hotel Paraiso, which Mr Nguema owns.

For Mr Obiang’s regime, long considered one of the most corrupt and repressive in Africa, Mann’s trial was a chance to confound its critics, to suggest that the tiny African state was more victim than victimiser. Unusually, it admitted foreign journalists, and made sure that Malabo’s diplomatic corps attended the trial in force to hear the former SAS officer and Old Etonian claim that there was an international conspiracy to seize the state’s vast oil riches.

Unprompted Mann said that his 2004 plot was in effect an “official operation”, sanctioned by the Spanish and South African governments, and tacitly endorsed by Washington. Sir Mark Thatcher was “part of the management team”, he said although all the available evidence suggests that he was merely an investor.

Mann said that a group led by Ely Calil, a London-based tycoon, was still conspiring to replace Mr Obiang with Severo Moto, an exiled opposition leader living in Spain.

Mann even expressed relief that his coup failed because he now realised that Equatorial Guinea was not such a bad place. Summing up, José Olo Obono, the Attorney-General, said the trial showed that Equatorial Guinea should never trust foreigners.

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