A senior judge at a special London court said there was a risk that evidence obtained using torture may be used against Abu Qatada and he may not receive a fair trial in Jordan.
The case of Qatada, a Jordanian cleric of Palestinian origin described by a Spanish judge as “Osama bin Laden’s right-hand man in Europe”, has been a thorn in the side of successive British governments.
Britain says videotapes of his sermons influenced Mohammed Atta, the ringleader of the Sept. 11, 2001 attacks on the United States.
The court ruled there was a “real risk” that evidence obtained by torture from two other men by could be used against him in a Jordanian court.
The ruling, delivered at a special court that deals with security cases, said British interior minister Theresa May had been wrong not to revoke an earlier deportation ruling against Qatada, and allowed his appeal.
The decision is a setback for May and the Conservative-led administration, both keen to foster an image of competence and decisiveness on security issues.
The court was considering whether to grant bail to Qatada, who has been in and out of jail in Britain since his arrest in 2002, spending seven years in detention without charge.
Jordan has convicted him in his absence of sending encouragement to militants there who were planning two bomb attacks in 1999 and 2000.
May’s department said in a statement it strongly disagreed with the ruling and would seek leave to appeal.
Robin Tam, a lawyer for the British government, told the court that Qatada “remains a man who poses an enormous risk to national security.”
Britain had argued that a 2005 deal with Jordan and more recent diplomatic assurances would ensure that Qatada would obtain a fair trial there.
It had maintained that the agreements with Jordan were sufficient to overcome a ruling by the European Court of Human Rights that Qatada could not be deported because of the possibility that a trial there could use torture evidence.