London - Freed mercenary Simon Mann has expressed his gratitude for being able to return to Britain after serving time in prison for attempting to overthrow the government of Equatorial Guinea.

Mann's private plane landed at Luton Airport after leaving the steamy island capital of the tiny Central African nation early on Wednesday.

He was pardoned by President Teodoro Obiang after serving 15 months of a 34-year sentence for scheming to overthrow the oil-rich government.

Mann did not speak to reporters. But his spokesman, Ian Monk. says he was "hugely grateful to President Obiang" after 5? tough years in prison.

Before leaving Equatorial Guinea, Mann said former British Prime Minister Margaret Thatcher's son and others should face justice for the coup plot. - Sapa-AP