Equatorial Guinea wants Mark Thatcher, son of former British Prime Minister Margaret Thatcher, extradited from South Africa after his arrest on suspicion of involvement in a coup attempt, one of the country's lawyers said on Thursday. "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," Lucie Bourthoumieux, a lawyer representing the central African country, told Reuters. "Now we have to wait for the response. This is really just the start of the process." Thatcher was arrested on Wednesday in South Africa on suspicion of helping to bankroll a plot to oust the president of tiny Equatorial Guinea, sub-Saharan Africa's third biggest oil producer, and install an exiled opposition leader. Thatcher, who has protested his innocence, has been put under what amounts to house arrest. South Africa's foreign ministry said earlier it could not respond to questions on whether he might be extradited because such a request had not yet been made. Eighty-four foreigners, mostly South Africans, are on trial simultaneously in Zimbabwe and Equatorial Guinea in connection with the alleged plot. --SP 2343 Local Time 2043 GMT