Two extremists linked to the failed July 21 bomb plot are among at least seven foreign-born terrorists who should have been deported but are still free to walk the streets, sources have confirmed.
Most are using human rights laws to stay in the UK, claiming they would face ill-treatment if sent back to their home countries.
Siraj Ali, who allowed some of the July 21 attack gang to stay in his flat while they were making the bombs and also helped clear incriminating evidence from the bomb factory at a friend's home, was released earlier this year.
Ali, who was jailed for nine years for failing to disclose information about terrorism and assisting an offender, was pictured walking the streets of north London last week.
He claims it would breach his human rights to deport him to the African state of Eritrea.
Ismail Abdurahman, who looked after terrorist Hussain Osman immediately before he fled the country on July 26, 2005, has also been released on licence after serving part of an eight-year jail term.
He is fighting deportation to Somalia.
Under Article Three of the European Convention on Human Rights, which is enshrined in UK law under the Human Rights Act, individuals are protected against torture, inhuman or degrading treatment.
A Home Office spokesman said: "We believe any foreign criminal convicted of a serious terrorism-related offence should be removed from the UK at the earliest opportunity, and where possible held in immigration detention until deported.
"We are currently pursuing deportation against a number of individuals and will consider action against the rest towards the end of their sentences."