Sir Mark Thatcher has been subpoenaed to appear before a South African magistrate to answer questions related to his alleged financing of a failed coup in oil-rich Equatorial Guinea.
The subpoena follows a request by the African country's government to question Mr Thatcher, the son of former Prime Minister Baroness Thatcher.
A delegation from the attorney general's office in Equatorial Guinea met with South African officials on Monday and the request was finalised. Their questions were forwarded to the chief magistrate in Cape Town, where Mr Thatcher is charged with contravening South Africa's Foreign Military Assistance Act.
Mr Thatcher, who is free on bail, will have to appear before a magistrate on September 22nd to answer the questions under oath.
Equatorial Guinea wants to question a number of prominent Britons about allegations they financed a plot to overthrow President Teodoro Obiang, who has ruled Africa's third-largest oil producer for the past 25 years.
At Guernsey's Royal Court, lawyers tried to block moves to unveil more of the supposed financial backers of the alleged coup attempt. President Obiang had obtained an order for the full details of people paying money into accounts in Guernsey to be disclosed.
They include an as yet unidentified JH Archer who paid nearly £75,000 into a Guernsey based account. Lord Archer has denied involvement in the coup.
President Obiang has already launched a multi-million pound civil action against the alleged coup leader, Mr Simon Mann, and others in the British High Court seeking damages for what he says was an attempt to overthrow him earlier this year.
Lawyers representing one of the companies to whom details of payments are being sought accused Equatorial Guinea of trying to use civil proceedings to garner evidence for use in a criminal case against the alleged plotters. The case was adjourned.
AP