A radical cleric once described as "Osama bin Laden's right-hand man in Europe" has been freed from a British prison.

Abu Qatada will live under virtual house arrest after a court ruled that his detention without trial was unlawful.

The Jordanian preacher must wear an electronic tag to allow the police to keep track of him, spend 22 hours a day at his family home and is banned from using the internet and mobile phones.

Twice convicted in his absence in Jordan of involvement in terrorist plots, Britain says he is still a national security risk and should be deported before London hosts the Olympic Games in July and August.

Britain says videotapes of his sermons were found in a German apartment used by three of the people who carried out al-Qaeda's 11 September, 2001 attacks on the US.

Mr Qatada was released from the high-security Long Lartin prison in central England on Monday night, a source familiar with the case said.

The government declined to comment.

Television pictures showed him being driven out of the prison in a van.

The 51-year-old, whose real name is Omar Othman, has been in and out of jail since he was first detained without charge under British anti-terrorism laws in 2002.

Mr Qatada, a father-of-five who had been living in London, denies belonging to al-Qaeda.

If he returns to Jordan, his lawyers say he risks being tortured or retried using evidence extracted from others using torture.

Under strict bail conditions, he will only be allowed out of the house for two hours each day and visitors must vetted.

Mr Qatada cannot go to mosques or lead prayer sessions.

His bail papers say that if he bumps into a friend in the street, he must "after any initial greeting, disengage himself from the situation whether by explaining the terms of his bail order or by making an excuse".