Thatcher: the net tightens

Witness set to hand key documents to South African investigators

A computer expert in possession of a list which reveals the identities of the rich and influential figures who allegedly backed the Equatorial Guinea coup plot has become an important witness for the prosecution.

The Independent has learnt that James Kershaw is preparing to give evidence in South Africa in any future trial of Sir Mark Thatcher, who is accused of involvement in an alleged plot to depose the president of the oil-rich west African state.

Mr Kershaw, 24, is believed to be in possession of what has become known as the "Wonga List" - details of people, including public figures in Britain, who allegedly bankrolled an attempt by mercenaries to overthrow the regime of President Teodoro Obiang Nguema and replace it with members of exiled opposition groups.

It is claimed that in return the backers would have been paid millions of pounds by the new government, as well as landing lucrative oil contracts.

The decision by Mr Kershaw to do a deal with the police means the secret "Wonga List" is now likely to be in the hands of the South African authorities, and details of those involved in the alleged coup plot are likely to emerge in the near future.

South African police officials said yesterday they were examining all the evidence obtained so far, and anticipated further arrests. They have refused to rule out seeking arrests and the extradition of suspects from Britain.

Mr Kershaw, who was born in South Africa but holds a British passport, has been named in court by a number of the arrested mercenaries as one of the recruiters in the alleged attempt to depose President Obiang.

He allegedly made a down payment of $90,000 (£50,000) in the Zimbabwean capital, Harare, and also allegedly gave last-minute instructions, by telephone, to those involved in the plot.

Mr Kershaw made the decision to co-operate with the authorities after seeking legal advice. He is believed to have met officials recently in South Africa, but it is not known whether he is still in that country or whether he has returned to Britain.

Authorities in Equatorial Guinea have announced that it wants Sir Mark extradited from South Africa.

"The process for requesting extradition has started. There has been a first contact, an initial expression of interest from the government of Equatorial Guinea to South Africa," said Lucie Bourthoumieux, a lawyer representing the country.

South Africa's foreign ministry said earlier that it could not respond to questions on whether he might be extradited because such a request had not yet been made.

Sir Mark appeared to have been on the point of leaving South Africa when he was arrestedover his alleged involvement in the plot. He had sold his four cars, put his house in Cape Town up for sale for £1.8m and reserved flights to the United States for his wife and children next week.

Sir Mark's lawyers denied he was trying to flee the country.

It was also claimed last night that he had received death threats from associates of the mercenaries allegedly involved in the plot.

The revelations about the "Wonga List" come as trials take place in two countries over the alleged coup plot.

It is claimed that Briton Simon Mann, an African mercenary, was the ringleader of the alleged coup attempt. He was held in Zimbabwe, allegedly with a plane full of mercenaries on their way to overthrow the Equatorial Guinea government.

The alleged plotters were said to be hoping to exploit the country's massive oil reserves after overthrowing President Obiang and installing their own leader, Severo Moto, currently in exile in Spain. Mann is one of 70 defendants held in Zimbabwe while another 19 people are on trial in Malabo, capital of Equatorial Guinea.

The 19 defendants in Malabo are charged with attempting to assassinate a head of state, illegal possession of arms and explosives, terrorism, treason and endangering the public. Verdicts in their cases are expected on Saturday.

One of the defendants, from Germany, died in prison in Equatorial Guinea. The human rights organisation Amnesty International said it suspected that he had been tortured.

Equatorial Guinea, which pumps out 350,000 barrels of oil a day, has become Africa's third-largest oil producer since offshore development began in the mid-1990s.

President Obiang has ruled the nation with an iron fist since 1979, when he overthrew the former dictator, his uncle.