Mark Thatcher part of Eq. Guinea plot

The son of former British Prime Minister Margaret Thatcher was a leader of a 2004 coup plot in Equatorial Guinea that was backed by Spain and South Africa, a British mercenary told a court on Wednesday .

Simon Mann, an Eton-educated former special forces officer, was giving testimony at his trial in Malabo about his role in the failed plot to overthrow President Teodoro Obiang Nguema Mbasogo in the small, oil-rich West African nation.

Answering questions from the prosecution, Mann said Mark Thatcher, who has denied knowing about the conspiracy, "was not just an investor".

"He came on board completely and became part of the management team," Mann said, adding that a London-based millionaire, Eli Calil, was "the boss" of the plot.

Mann also said the governments of Spain and South Africa knew about the conspiracy and approved of it going ahead.

Spain's Foreign Ministry quickly denied the allegation.

Mann was arrested in Zimbabwe in March 2004 with 70 mercenaries en route to Equatorial Guinea, a former Spanish colony which Obiang has ruled since 1979.

On the first day of Mann's trial on Tuesday, the prosecution asked the court to jail him for nearly 32 years for his role in the coup plot, which he has admitted being part of. His defence lawyer said he was an "instrument", but not a ringleader.

Mann, 55, testified on Wednesday that by January 2004, the coup plot had become "like an official operation because the Spanish government and the South African government were both giving the green light".

"Their involvement was clandestine and they will never admit it," he told the court.

"We totally deny what Mr Mann says. We did not give the green light to any of this," a Spanish Foreign Ministry spokesman said in Madrid.

Equatorial Guinea's Public Prosecutor Jose Olo Obono told Reuters the next step for the West African state's authorities would be to seek the extradition of Thatcher and Calil.

"I am very, very sorry for what I have done. I am also very happy that we failed ... I think that the people that were seriously involved in this and have not faced justice, they should do so," Mann told the court