Muslim cleric Abu Qatada is due to be released on bail after winning the latest stage in his seven-year legal battle to avoid deportation to Jordan, where he faces terrorism charges.
He will be released from Long Lartin prison, in Worcestershire, later.
The Special Immigration Appeals Commission decided his trial in Jordan, over suspected bomb plots, might not be fair because evidence obtained by the torture of others could be used.
The government is planning a challenge.
Home Secretary Theresa May has branded the Siac ruling “deeply unsatisfactory” and has said the government will try to appeal against the decision.
Jordan’s acting information minister Nayef al-Fayez told the BBC his government shared UK authorities’ disappointment at the Siac ruling.
Abu Qatada, whose real name is Omar Othman, has been in detention in Britain for seven years – although he has never been charged with a crime in the UK.
Earlier this year, judges at the European Court in Strasbourg ruled the cleric would not face ill-treatment if returned to Jordan, citing assurances outlined in a UK-Jordan agreement.
Crucially, however, the judge did not believe he would get a fair trial because a Jordanian court could use evidence against Abu Qatada that had been obtained from the torture of others.
On Monday, despite the UK obtaining additional assurances from Jordan, Siac chairman Mr Justice Mitting ruled he was not satisfied Abu Qatada would be tried fairly.
Criminal code
David Anderson QC, the Independent Reviewer of Terrorism Legislation, told the BBC: “The key to this case really lies in Jordan.
“What the judge said, what the court said in terms, was that a simple amendment to the Jordanian criminal code so as to remove an ambiguity that is in it at the moment ought to suffice to make deportation possible, because it would then be possible to say without fear of contradiction that Abu Qatada, if placed on trial back in Jordan, would not be tried on the basis of evidence obtained by torture,” he told Radio 4’s Today programme.
Home affairs committee chairman Keith Vaz, who branded the Siac ruling “farcical”, said the king of Jordan would be visiting the UK later this month, which gave the government “an opportunity to try and persuade him to go that little bit further in terms of the way the criminal code of Jordan operates”.
The case had cost taxpayers £1m, he said.
Human rights lawyer Julian Knowles warned that it could drag on for years.
“We’ve got another year’s worth of UK litigation at least. And then if Abu Qatada is the loser at the end of the domestic phase, he can then go back to the European Court and say, ‘Look, the English courts have misunderstood the evidence.’
“The European Court will look at the position as it then is in 2014 or 2015 or whenever it is, and there is a possibility therefore that we are in for several years more of litigation.”
The bail conditions imposed by Mr Justice Mitting on Abu Qatada include being allowed out of his house only between 08:00 and 16:00, having to wear an electronic tag, and being restricted in whom he meets.
Abu Qatada faces a re-trial in Jordan for allegedly conspiring to cause explosions on Western and Israeli targets in 1998 and 1999. He was found guilty of terrorism offences in his absence in Jordan in 1999.
The Palestinian-born Jordanian has been described as the spiritual leader of the mujahideen. Security chiefs believe he played a key ideological role in spreading support for suicide bombings.
Keith Best, from the charity Freedom from Torture, said: “This really ought to be a wake-up call that those who live by the sword, perish by the sword, and if states continue to try to obtain evidence by torture – notoriously unreliable by the way – then those states have got to learn that if they want to prosecute people in the courts, those prosecutions will probably fail.”