Why are we asking this now?
Simon Mann, the Eton-educated former SAS troop leader who organised a coup against the president of the oil-rich African state of Equatorial Guinea, arrived back in Britain yesterday after receiving a pardon.
He had served 15 months of a 34-year prison sentence imposed last June. The release of the 57-year-old Briton re-opens a gamut of uncomfortable questions about who funded the botched power grab in March 2004, not least from detectives at Scotland Yard's counter-terrorism command. Officers are expected to interview Mr Mann as part of an investigation into whether any offences were committed in Britain during the planning of the operation, involving some 64 battle-hardened South African mercenaries and a small fleet of aircraft. The amount of money paid to bankroll the plot, and its potential multi-million-dollar rewards, earned it the sobriquet of the "Wonga Coup".
What happened in March 2004?
The first the outside world knew of the clandestine operation to depose President Teodoro Obiang Nguema, who has ruled his tiny west African nation with a rod of iron since seizing power in 1979, was news of the arrest of a plane-load of mercenaries on board an ageing Boeing 727 at the airport in the Zimbabwean capital, Harare. Mr Mann, rapidly identified as leader of group, claimed he and his colleagues were en route to guard a mine in the Democratic Republic of Congo. But it soon became clear that the men were in Harare to pick up a consignment of small arms to be used in the operation to replace President Obiang with a Madrid-based opposition leader, Severo Moto.
Details then emerged of a plot which could have been culled from the pages of an airport thriller: Mr Mann, at the time based in Cape Town, had been persuaded to spearhead a plot organised by a shadowy group of businessmen to seize control of Equatorial Guinea's oil production of 450,000 barrels per day – the third highest in sub-Saharan Africa. Intelligence intercepts and a letter smuggled out of Harare's notorious Chikurubi prison by a desperate Mr Mann revealed the aliases of his alleged co-conspirators as "Smelly", "Scratcher" and the "Cardinal".
So who were Scratcher, Smelly, and the Cardinal?
According to testimony given by Mr Mann to his trial last year in Equatorial Guinea (where he was spirited from his Harare prison cell after Zimbabwe's President Robert Mugabe struck a deal for $7m of Mr Obiang's oil), "Scratcher" was Mark Thatcher, the son of the former prime minister, and "Smelly" and "Cardinal" were nicknames for Ely Calil, a Lebanese-Nigerian billionaire based in London. Mr Mann, who had struck a private deal with the Obiang regime to reveal all about the coup, claimed that Thatcher was "part of the management team" for the plot and that it had been originated by Calil. Both men have always insisted they had no knowledge of or involvement in the operation.
Was Mark Thatcher really a key player?
Described by one acquaintance as having "an ego the size of a herd of elephants and the attention span of a gnat", Thatcher was accused by Mr Mann of being at the heart of the planning for the coup and "not just an investor". Court documents showed that Thatcher paid $275,000 (£140,500) for a helicopter to be used by one of the coup participants, Crause Steyl, a gung-ho South African pilot. Thatcher was arrested at his South African home in 2005 and struck a plea bargain with prosecutors by pleading guilty to unknowingly helping to finance the plot. He was fined and given a suspended jail term after insisting he thought the helicopter was to be used as an air ambulance.
How did Thatcher and Mr Mann know each other?
They were neighbours in Constantia, the well-heeled and breathtakingly pretty suburb Cape Town which is favoured by expats attracted by the area's rows of gated villas with large swimming pools. Over cocktail parties and glittering soirees, Mr Mann, the son and grandson of England cricket captains and the scion of a brewing dynasty, became a close acquaintance of Thatcher, who in turn introduced the debonair SAS man to his mother. Mark Thatcher once said: "Simon is my best friend." Mr Mann insists that by 2003 the two men were sufficiently close to jointly participate in the Wonga Coup. Thatcher, who now lives in southern Spain and is wanted along with Calil for questioning by the Equatorial Guinean authorities, insists otherwise.
What about Ely Calil?
The reclusive billionaire (who until recently had not been photographed since 1972) admitted in an interview last year that he had introduced Mr Mann to Moto and financed the opposition leader's political activities. But he said he had only ever supported "democratic change" in Equatorial Guinea and the plot detailed by Mr Mann was "pure fantasy". Calil said: "I am not a coup plotter. I don't have a talent in that sense."
Just what did the coup leaders hope to gain?
In return for deposing one of Africa's longest-standing, richest and most autocratic rulers, the plotters were apparently expecting vast wealth. According to a document presented at Mr Mann's trial, he had negotiated a $15m (£9m) "success fee" as well as access to lucrative security contracts to guard the new Moto regime. Each of his lieutenants was also to receive £1m but the real reward lay in a share of Equatorial Guinea's oil royalties, which amount to some £40m a day.
Did the CIA play any role in the failure of the coup?
American oil companies, including Exxon Mobil and Chevron Texaco, have a substantial presence in Equatorial Guinea and there have long been suggestions that the CIA blew the whistle on the plot to protect US interests. Washington has refused to respond but the States is just one country accused of prior knowledge of the coup. Whether its knowledge came from the CIA or not, it was South African intelligence which tipped off the Zimbabwean authorities about the mercenaries at Harare airport. Spain and Britain have also been accused of tacitly approving the "regime change" operation.
Are mercenaries a thing of the past?
South African legislation banning so-called "dogs of war" has drastically reduced mercenary activity but it is by no means a thing of the past. From Sudan to the Ivory Coast, there are reports of foreign soldiers directing and fighting in African conflicts. This week it emerged that £27m of small arms had been shipped to a junta in Guinea in defiance of an arms embargo with the help of South African "security advisers".
What now for Mr Mann?
After five-and-a-half years in jail, the father-of-seven made clear yesterday his mercenary days were behind him. Instead, he is expected to finish a memoir about the saga ahead of a mooted Hollywood film. It is possible that Mr Mann could play an on-screen role. He made an improbable debut as an actor in 2002, playing the role of a Parachute Regiment commander in Bloody Sunday.
Have we seen the last of mercenary-led coups?
*Since 1998, South Africa has banned mercenary activity, deterring large numbers of "dogs of war"
*The African Union now refuses to recognise leaders who seized power by force
*Security contracts in Iraq and Afghanistan provide an alternative source of employment
*"Hired guns" are as old as conflict itself. South Africa alone has 3,000 ex-soldiers looking for work
*From South Sudan to Guinea, mercenaries are active in propping up regimes or supplying arms
*Outsourcing military operations to private companies is increasingly popular among weak governments