Abu Qatada, a radical Muslim cleric whom British officials say is an al-Qaeda figurehead and a threat to national security, was freed from an English prison into virtual house arrest late Monday, British media reported.

Judicial officials acknowledged earlier in the day that the 51-year-old extremist preacher's release from Long Lartin jail was imminent, but declined to comment on the reports from Sky News and the BBC, citing operational concerns.

Both broadcasters aired photographs that appeared to show Abu Qatada in the backseat of a van as it left the high-security prison in central England.

The Palestinian-Jordanian cleric has spent more than six years in prison, but a tribunal ruled last week he should be released on bail.

Ordered to wear an electronic tag

The terms of his bail, published by the judiciary, require Abu Qatada to wear an electronic tag and to stay inside his home for 22 hours each day. He is not allowed a mobile phone, a computer or Internet access, and he is barred from communicating with a long list of individuals, including al-Qaeda leader Ayman al-Zawahiri.

The conditions also stipulate he must not lead prayers, give lectures, publish articles, preach or provide religious instruction or advice, "other than to his wife and children at his residence."

Abu Qatada, whose real name is Omar Mahmoud Mohammed Othman, has been described in both Spanish and British courts as a leading al-Qaeda figure in Europe. He is reported to have had close ties to the late Osama bin Laden.

British officials say he poses a serious threat to the country's security, but attempts to deport him to Jordan to face terrorism charges was blocked by the European Court of Human Rights, which ruled last month that there is a risk evidence obtained through torture would be used against him in court.

PM looking at 'options' to remove cleric

Prime Minister David Cameron's office said Monday that Britain still hoped to overcome the European's courts objections. Jordanian officials also have said they will challenge the ruling.

"We are clear we want to remove Abu Qatada at the earliest opportunity. We are looking at all the options," a spokesman for Cameron said, on condition of anonymity in line with policy.

Abu Qatada arrived in Britain in 1993 and was detained in 2002 under anti-terrorism laws that at the time allowed suspected terrorists to be jailed without charge. He has never been charged with a crime in Britain, although authorities have accused him of advising militants and raising money for terrorist attacks.

Although Abu Qatada was released in 2005 when the unpopular law was overturned, he was kept under surveillance and arrested again within months and held pending deportation to Jordan.

He has been convicted in absentia there of terrorist offences related to two alleged bomb plots in 1999 and 2000, and would face a retrial there if deported from Britain.