A statement on a militant website says al-Qaida's north African branch has offered to release a British man abducted in Mali if Britain frees radical Islamist cleric Abu Qatada.

The statement attributed to al-Qaida in the Islamic Maghreb (AQIM), which could not be verified, said the group would release Stephen Malcolm, who was taken from the northern Mali town of Timbuktu last November along with two other Westerners.

But the message also warned Britain not to deport Qatada to his native Jordan, where he was convicted in absentia in 1998 of terrorism charges related to two bomb plots.

Britain re-arrested Qatada earlier this month, renewing efforts that began in 2001 to send him back to Jordan. The move has been repeatedly blocked by the courts, including in January when the European Court of Human Rights ruled against the deportation, because evidence used against the cleric in Jordan may have been obtained using torture.

Jordan's justice minister has said Qatada would be entitled to a new trial.

British officials have described Qatada as former al-Qaida leader Osama bin Laden's top European deputy. He has been detained for most of the past decade under the country's anti-terrorism laws.