Thatcher 'in a third country' as he waits for a US visa to join wife

Sir Mark Thatcher, who left South Africa last week after pleading guilty to involvement in an African coup plot and paying a £300,000 fine, has gone to ground while seeking entry to the US.

Sir Mark Thatcher, who left South Africa last week after pleading guilty to involvement in an African coup plot and paying a £300,000 fine, has gone to ground while seeking entry to the US.

"I can't tell you where he is, but it is not in Britain," Mark Worthington, a spokesman for the family, said yesterday. "He needs to sort out his visa for the US, and in the meantime he is in a third country."

Baroness Thatcher's son wants to join his American wife Diane, who is living with their two children in Texas, but the US embassy in London said British citizens with a felony conviction have to apply for a visa to enter the US, and "each application will be considered separately".

Sir Mark was arrested at his Cape Town mansion in August by South Africa's elite Scorpions investigation unit and charged with helping to finance an attempted coup in the oil-rich African state of Equatorial Guinea.

The plot collapsed when an arms shipment and a planeload of alleged mercenaries were seized in Zimbabwe last March.

Sir Mark's friend, Simon Mann, an Old Etonian and former SAS officer, and more than 60 ex-members of South Africa's apartheid-era special forces have been jailed in Zimbabwe and Equatorial Guinea for their roles.

The former prime minister's son was freed from house arrest after Lady Thatcher put up £180,000 bail, but his passport was impounded, he was restricted to the Cape Town area and had to report to the police daily. He insisted that although he knew several people implicated he was ignorant of the plot. He said his $275,000 (£150,000) investment in a helicopter company run by one of them was for an air ambulance venture.

In the plea bargain accepted by the Cape High Court on Wednesday, however, Sir Mark admitted he had begun to suspect a chartered helicopter "might in fact be intended for use in ... mercenary activity", but went ahead with the deal, contravening South Africa's Foreign Military Assistance Act (FMAA). He was sentenced to five years, with an additional four years suspended, or a £300,000 fine.

A source in South Africa said the Scorpions were "delighted" with the verdict, since, despite the claim they had a cast-iron case, their evidence was circumstantial. Previous attempts to bring cases under the FMAA have collapsed. Sir Mark's associates said he had pleaded guilty purely to cut short a process which threatened to keep him in South Africa for years, separated from his family and unable to do business.

"It should be noted that Sir Mark was not charged with any involvement in the attempted coup d'etat in Equatorial Guinea," said a statement from his lawyers. "The plea bargain was entered into solely as a result of his financing of the charter of a helicopter in circumstances where he should have exercised more caution."

In addition to his criminal record, Sir Mark may still be pursued by lawyers for Equatorial Guinea, which won permission to question him under oath in South Africa, a decision he was fighting.

A spokesman for the Scorpions, Sipho Ngwema, responding to complaints the financier had got off lightly, said Sir Mark had agreed to co-operate with the investigation. "He has assured us he will be available anywhere in the world," said Mr Ngwema. "We are going to be in touch with him for a long time."