Simon Mann was jailed in 2004 following his conviction on charges of trying to buy weapons without a licence as part of a plot against Equatorial Guinea President Teodoro Obiang Nguema Mbasogo.

Mann, 55, was briefly released after serving his sentence in May last year but was again arrested on an immigration warrant while awaiting deportation.

His lawyer, Jonathan Samkange, told journalists that immigration authorities had deported Mann on Wednesday night soon after the Zimbabwe High Court rejected arguments that he should not be extradited because he might be tortured over the coup charges in Equatorial Guinea.

Samkange -- who on Thursday filed an appeal at the Supreme Court against the High Court decision -- said he had only discovered later in the day that Mann may have been deported.

"They deported him at night late on Wednesday. There are (state) affidavits to that effect," he told journalists.

Mann was arrested in March 2004 when he met a plane carrying dozens of men and military equipment which landed in Harare on what officials said was the first stop on their way to launching a coup against Obiang.