Abu Qatada, a radical Muslim cleric dubbed "Osama bin Laden's right-hand man in Europe", succeeded Wednesday in the latest step of his fight to avoid deportation from Britain.
The 45-year-old Jordanian national won his appeal against a 2007 decision that he could be deported to Jordan because he was not at risk of torture in his home country, where he has been convicted of terror attacks.
The Court of Appeal said Wednesday it was concerned that evidence alleged to be obtained under torture in Jordan may be used in any future trial involving him there.
The British government said Qatada would not be released from jail, and it would appeal against the ruling. Qatada has been described by a senior Spanish judge as Osama bin Laden's main contact in Europe. Tapes of Qatada's sermons were found in a flat in the German city of Hamburg used by some of the September 11 hijackers.
The decision came alongside another legal decision which led the government to drop efforts to deport 12 terror suspects to Libya. The rulings deal a blow to the government's policy of signing memoranda of understanding with countries with poor human rights records, announced by then premier Tony Blair in 2005 as part of a crackdown on suspected militants after the London bombings.
Memoranda of understanding bid to ensure that terror suspects being deported back to such countries are not tortured, ministers say. But human rights organisations have long criticised the agreements, saying they are virtually worthless and threaten the global ban on torture.
Wednesday's decision was welcomed by Amnesty International, whose spokesman Tim Hancock said: "Everyone has a right to a fair trial and if Abu Qatada is suspected of wrongdoing, he should be fairly tried, not shipped off to Jordan to be sentenced on the basis of evidence that was tortured out of someone. "The government should abandon its attempts to get round the global ban on torture using assurances and play by the rules."
Home Office minister Tony McNulty said: "I am pleased that the courts dismissed all but one of Abu Qatada's reasons for appeal. "I believe that we will be able to secure his deportation to Jordan and we will push for it as soon as possible."