JOHANNESBURG, Aug 26 (AFP) - South Africa served notice this week that it is ready to chase big fish like Mark Thatcher in its campaign to outlaw mercenaries and put an end, once and for all, to the work of private armies on the continent.
The arrest of former prime minister Margaret Thatcher's son at his luxurious Cape Town suburban home on Wednesday came nearly six months after South Africa tipped off the oil-rich state of Equatorial Guinea of a plot to topple its longtime leader Teodoro Obiang Nguema.
Pretoria also told its Zimbabwean neighbours that some 70 men -- all travelling on South African passports -- were on their way to Harare airport on March 7, allegedly on their way to stage the coup in Equatorial Guinea.
Meanwhile another 15 men, including eight South Africans, were detained on similiar charges in Malabo.
"The scope of South Africa's investigations has now moved upward," said senior researcher Angela McIntyre of the Pretoria-based Institute for Security Studies.
"They have obviously recognised that the players in this whole saga are at higher levels than what might have been the initial impression."
Thatcher, 51, a millionaire businessman, has been charged with violating the 1998 Foreign Military Assistance Act, passed by the African National Congress government four years after it swept to power with the end of apartheid.
He is accused of contributing 275,000 dollars to the plot that would have allegedly seen a new regime take hold in Malabo, where the recent discovery of oil has drawn attention to the small central African country.
Thatcher has been linked to one of the alleged masterminds of the coup plot, Briton Simon Mann, a former Special Air Services member who is among the 70 suspected mercenaries currently on trial in Zimbabwe.
South Africa allowed the raid on Thatcher's house to be carried out on the day that Foreign Secretary Jack Straw arrived in Cape Town at the head of the biggest ever British delegation to South Africa.
It also signalled that Thatcher would not be the last to answer charges with Deputy Justice Minister Johnny de Lange saying "a limited number of individuals were being investigated" for violations of the anti-mercenary law.
"We don't like the idea of South Africa becoming a cesspool of mercenaries," Foreign Affairs Minister Nkosazana Dlamini-Zuma said after the arrests in Zimbabwe and Equatorial Guinea in March.
Safety and Security Minister Charles Nqakula has called for a review of the act -- which has been criticised for being too broad -- to "ensure that we plug all the gaps".
South Africa's history as a seedbed for mercenaries dates back to the 1960s when its men fought in the Belgian Congo but it took off in the early 1990s when the end of apartheid put many highly trained soldiers on the market for lucrative work.
Of the myriad of security firms and "private armies" that emerged from South Africa, the most well-known is Executive Outcomes, co-founded by Mann, who is Thatcher's neighbour.
It helped the Angolan government protect oil installations from rebels during the civil war and its spinoff firm, Sandline International, was involved in Sierre Leone.
The apartheid government also set up a mercenary unit called the "Buffalo Battalion" in the 1970s to fight in Namibia and Angola, recruiting foreign soldiers, many from Portuguese-speaking countries.
The unit was disbanded in 1993 and the South African government offered the mercenaries citizenship, an offer most of them accepted.
McIntyre said it was "commendable" that South Africa was now trying to stamp out mercenary activities, but the government needed to take into account that the country had a "lot of surplus military capacity".
"They are there and they are seeking opportunities that are out there. The sector needs to be regulated. We need to come up with acceptable mandates and then decide who should stay and who should go."