A British man sentenced to 34 years in jail for his part in a failed coup in Equatorial Guinea has been granted a presidential pardon and is expected to leave the West African country within 24 hours.Simon Mann's release comes only a 1 1/2 years into a 34-year sentence. In 2008 he admitted plotting to oust Equatorial Guinea's President Teodoro Obiang Nguema. But the country's chief judge said Mann and four South African accomplices would be freed Tuesday after the conspirators were given a full pardon by the country's president. A presidential advisor has told British media that Mann, 57, who had a hernia operation last year, had been released on humanitarian grounds related to his health. Africa analyst Patrick Smith says rumors have been circulating for some time that Mann would be released. But the timing, he says, is surprising. He says normally President Obiang makes grand announcements during elections or on national holidays. Smith told VOA that by freeing the prisoners, President Obiang might be trying to improve his international image. "Some people are linking it to the fact that President Jacob Zuma of South Africa is due in the country soon and President Obiang wanted to relegate the Equatorial Guinea coup plot -- and Simon Mann's involvement in it, along with a lot of South Africans-wanted to relegate that to history," he said. Mann was arrested along with 63 others in 2004 when his plane landed in Zimbabwe allegedly to collect arms bought from the country's state arms manufacturer. He was extradited to Equatorial Guinea in 2008. Mann said at the time that he had been the "manager, not the architect" of the coup plot. The conspirators planned to install exiled opposition leader Severo Moto as president and to gain control over the country's vast oil supplies. Equatorial Guinea is Africa's third biggest oil producer. Smith says during Mann's trial he implicated others in the conspiracy including Lebanese businessman Elie Khalil and the son of Britain's former prime minister. "Simon Mann has consistently pointed fingers at others involved in the coup plot and those would include the son of the former British Prime Minister Margaret Thatcher and that man is Mark Thatcher," he said. Mark Thatcher, who now lives in Spain, was fined and received a suspended sentence in 2005 for his role in helping to finance the plot. President Obiang has been in power in Equatorial Guinea since taking power in a coup in 1979. He has won a number of multiparty elections since 1991 and in 2002, he won over 90 percent of the votes. Elections are set to take place at the end of this month.