Thatcher turns up at court in bid to block coup-plot questions

Dressed in a blue blazer and tapping a pen on his knee, a defiant Sir Mark Thatcher appeared in court yesterday to fight an attempt to force him to answer questions about his alleged role in a coup plot.

The son of Baroness Thatcher made notes and listened intently as his legal team presented an 80-page argument to the High Court in South Africa in an effort to overturn a subpoena obtained on behalf of the government of Equatorial Guinea. Prosecutors in the oil-rich west African state want to ask Sir Mark about a coup attempt he is alleged to have helped fund by buying aircraft to carry mercenaries seeking to overthrow President Teodoro Obiang Nguema.

Barristers acting for Sir Mark claimed that the demand would prejudice his forthcoming trial in South Africa on charges of breaking a law banning residents from aiding foreign military action. Alan Bruce-Brand, for Sir Mark, said he was defending his client's "right to remain silent". The lawyer told the court: "It is contended by our legal team that this questioning is an inappropriate and improper procedure."

The appearance of Sir Mark at the beginning of the two-day hearing to decide the validity of the subpoena issued by the South African justice ministry, had not been expected at the start of what will be a long and expensive legal saga.

But the presence of television cameras in the court - the first time that a case has been televised live in South Africa - is likely to have been deemed an unmissable chance for the defendant to protest his innocence. The smartly dressed businessman made no comment as he left court, besieged by cameras and reporters.

Equatorial Guinea has said it may seek to extradite Sir Mark. South African officials have already said they believe Sir Mark would receive a fair trial in Equatorial Guinea, despite claims that some of the 19 defendants on trial there accused of complicity in the plot have made confessions under torture. No request for the extradition of the former prime minister's son has yet been made, but his lawyers claimed that any trial in Equatorial Guinea would be unfair.

Peter Hodes, a member of the defence team, said: "What we are dealing with in Equatorial Guinea is a military tribunal, or there is a good possibility that it is."

Sir Mark was arrested at his luxury home in Cape Town in August by South African police investigating foreign involvement in the plot to replace President Nguema, an ageing despot, with Severo Moto, an exiled opposition leader.

The main allegation likely to be faced by Sir Mark is understood to be that he provided £145,000 towards the cost of the coup attempt, led by Simon Mann, a former SAS officer.

The money is alleged to have been used to lease an aircraft to fly Mr Moto to Equatorial Guinea and pay for transport for Mann and 67 mercenaries.

Last month a Zimbabwean court sentenced Mann, a friend of Sir Mark, to seven years in jail on charges of illegally obtaining weapons, allegedly for the coup.

Sir Mark, who faces 15 years in prison if convicted in South Africa, maintains that although he did make a payment to a business partner subsequently implicated in the plot, he believed he was making an investment in an air ambulance service. The two-day hearing in Cape Town will decide whether the Briton, who has lived in South Africa for nine years, should face the Guinean government's questions through a South African magistrate.

The lawyers for Sir Mark said they did not know when a judgment in the "very difficult case" could be expected.