British mercenary Simon Mann, convicted of involvement in a coup plot in Equatorial Guinea, has been pardoned.

The authorities say Mr Mann has been released on humanitarian grounds to allow him to seek medical treatment. The 56-year-old former British soldier has been expelled from the country and banned from returning.

Mr Mann's release comes after he has served only one year of a 34-year sentence. In his defence he maintained he was merely a pawn in a plot framed by international businessmen to seize power in Equatorial Guinea.

He also claimed that Mark Thatcher, son of former British prime minister Margaret Thatcher, had been involved. Mr Thatcher received a two-year suspended prison sentence in South Africa for unintentionally funding the coup plotters.

Another man involved in the alleged coup attempt, the South African Nick du Toit, has also been pardoned.