Abu Qatada, a radical Muslim cleric who British authorities claim is a threat to national security was freed on bail from prison late on Monday.

The release into virtual house arrest was agreed by a tribunal, after government efforts to have the 52-year-old extradited failed.

Qatada, 52, was freed under strict conditions after the European Court of Human Rights ruled last month that he could not be detained further without trial. The court in Strasbourg also found that he could not be deported to his native Jordan because there was a risk that evidence obtained by torture might be used against him.

Earlier on Monday, the office of British Prime Minister David Cameron said the government still hoped to overcome the European court's objections. "We are clear we want to remove Abu Qatada at the earliest opportunity," said a spokesman. "We are looking at all the options."

'Completely unacceptable'

Qatada has spent more than six years in prison, having first been detained in 2002 under a controversial anti-terrorism law. He was released in 2005 when that law was repealed, but kept under surveillance and later detained pending deportation to Jordan.

Cameron, increasingly under pressure from euroskeptics in his Conservative Party, said last week it was "completely unacceptable" that Britain was not able to deport or detain Qatada.

The terms of Qatada's release mean he will have to wear an electronic tag and stay inside his house for 22 hours each day, being allowed outside to pick up his daughter from school. He is not permitted to use cell phones or the Internet and is forbidden from contacting numerous individuals, including the al Qaeda leader Ayman al-Zawahiri.

The preacher is also forbidden from delivering religious instruction to individuals "other than his wife and children at his residence."

While Qatada has never been charged with a crime in Britain authorities accuse him of advising militant extremists and collection funds to support Islamist terrorism. Human rights groups have said he should face a full trial in Britain.

Officials in Jordan, where Qatada has been convicted in absentia of bomb plots in 1999 and 2000, have said that - like the British government - they also intend to challenge the Strasbourg ruling.

rc/ai (ape, Reuters, dpa)