A radical cleric who poses a serious risk to the UK's national security has been freed on bail under some of the toughest conditions imposed since the September 11 terror attacks, sources have said.

Abu Qatada was banned from taking his youngest child to school, must stay inside his home for 22 hours a day, and cannot talk to anyone who has not been vetted by the security services first.

Once described by a judge as Osama bin Laden's right-hand man in Europe, he was also banned from meeting 27 named individuals, including new al Qaida leader Ayman al-Zawahiri.

Qatada, 51, was in a van which left the high-security Long Lartin prison in Evesham, Worcestershire, for his London home at about 9.15pm. He was in the back seat and was seen hiding his face.

Qatada has been held for six-and-a-half years, more than any other detainee in modern immigration history, while fighting deportation.

But he was released after applying for bail when human rights judges in Europe ruled he could not be deported without assurances from Jordan that evidence gained through torture would not be used against him.

Under the terms of his release, the Home Secretary has just three months to show the Government is making significant progress in securing his deportation or risk Qatada being freed from his bail conditions.

These were agreed between lawyers earlier on Monday as a Jordanian government minister said the country was working with the UK Government to give the European Court of Human Rights (ECHR) the assurances it needed.

Qatada will only be allowed outside his London home in a prescribed area for two one-hour periods each day - and he will be kept in during the school run, sources said.

An edited eight-page summary of the terms released by the Special Immigration Appeals Commission (Siac) showed he will be banned from meeting 27 people, including al-Zawahiri, radical cleric Abu Hamza, and terror suspect Babar Ahmad.