The governor of a high-security prison in Worcestershire acted reasonably when he took steps to prevent a Muslim preacher "radicalising" young Muslim inmates, the High Court has ruled.
Two judges said radical cleric Abu Qatada, 49, was an "iconic figure for jihadists" and moves to restrict his possible "malign influence" at Long Lartin were justified and proportionate.
Qatada's real name is Omar Othman and he was once dubbed Osama bin Laden's right-hand man in Europe.
He is among six Muslim international terror suspects who are unconvicted of any offence but held in a special detainee unit at Long Lartin, near Evesham.
Qatada faces jail in Jordan for terrorism but alleges his conviction was based on evidence extracted by torture.
Lord Justice Aikens, sitting with Mr Justice Openshaw, rejected challenges to a decision by Long Lartin governor Ferdie Parker, in December 2008, to change the living conditions for all the detainees after Qatada returned to the unit.
The effect was to confine them to the unit for all purposes, except for healthcare and family visits, and ban them from mixing with other prisoners.
Qatada came from Belmarsh Prison in south east London, where he was accused of attempting to "foment trouble" and inciting other prisoners to challenge authority.
The Special Immigration Appeals Commission (SIAC) described Qatada as "an individual who preaches violence and seeks to radicalise his audience", the High Court heard.
Lord Justice Aikens said the case was not an easy one, but ultimately the court was persuaded the governor's decision was reasonable.
The judge declared that a governor of a high-security prison "must have a wide discretion" with regard to Category A prisoners and those suspected of terrorist acts outside the UK, even if they were unconvicted.
The ruling comes days after the BBC reported that radical Muslim gangs are imposing a form of Islamic law in the jail, with non-Muslim inmates being forced to stop playing "Western music" and to take down pictures of women in their cells.