Hate preacher Abu Hamza could escape extradition to the US because he faces a lengthy jail term if convicted, it emerged today.
In an astonishing ruling, European judges said sentences of up to 50 years for Hamza and three other alleged terrorists could breach their human rights.
The judgment is likely to send the cost of their already expensive legal battle spiralling with many more months of wrangling.
It will also raise further concerns about the European Court of Human Rights' interference in the British justice system.
The hook-handed radical, 52, and his trusted lieutenant Haroon Aswat, 30, are wanted by the US authorities for plotting to set up a jihadi training camp in Oregon.
Two other men, Baba Ahmad and Seyla Ahsan, are accused of conspiracy to commit terrorist atrocities overseas and supporting terrorist groups.
All have exhausted their rights of appeal in the UK courts and are being held in high security detention.
Their lawyers claimed that if extradited to the US the men faced trial by a military commission and a possible death sentence as well as the risk of 'extraordinary rendition' to another country.
But the court rejected these arguments, pointing to assurances from the US government that they would be prosecuted in the normal way.
Al Qaeda mastermind living in Britain faces extradition to U.S.
Police stripped of stop and search terror powers in victory for civil liberties
However, the judges said they would consider whether jail terms of up to 50 years without parole breached Article 3 of the European Convention on Human Rights, which bans 'inhuman or degrading treatment'.
For all the defendants except Hamza, they also agreed to examine whether their potential detention in so-called 'Supermax' high security prisons was also a breach of human rights.
A court drawing of Babar Ahmad, who has been fighting extradition for more than six years
So far Hamza's case has cost the public purse £1.1million in legal aid, but the case will now rumble on for many more months, at further cost to taxpayers.
Tory MP Patrick Mercer said: 'Mr Hamza ought to face justice. In the meantime he continues to live off the fat of the British taxpayer - despite the fact that he clearly wishes those very same taxpayers ill.'
Hamza - who know asks to be known as Mustafa Kamal Mustafa - is currently being held in Belmarsh high security prison.
As well as fighting extradition, he is also engaged in a separate legal battle against attempts by the Home Secretary to strip him of his British passport.
Last year it emerged prison bosses spent £650 on new sink taps in his prison cell.
He was also accused of preaching extremist sermons to other prisoner through the water pipes in his cell.
He was jailed for seven years in February 2006 for preaching hate and inciting murder at Finsbury Park Mosque in North London.
He would be eligible for release but remains inside while his extradition case continues.
Ahmad, 36, made headlines last year when he won £60,000 in damages from Scotland Yard after police admitted 'grave abuse tantamount to torture' when they arrested him in December 2003. He was held for six days then released without charge.
Home Secretary Theresa May said: 'We note that the European Court of Human Rights has decided that all the applications are partly admissible.
'We await the Court's judgment on the case. In the meantime these individuals will remain in custody.
'AL QAEDA MEMBERS' HELD OVER SUBWAY PLOT
Three suspected Al Qaeda terrorists with links to bomb plots in Manchester and New York were arrested in Norway today.
The three, who have not been named, were held in raids that followed months of surveillance there.
The move came after counter terrorism officials in Britain and the United States acted to bring members of a sprawling terror cell to justice.
Officials said the same top-level al Qaida masterminds were behind the plots in all three countries.
Prosecutors in the United States want to put five men on trial over a suspected July 7-style peroxide suicide bomb plot targeting the New York subway.
One of them is Pakistan-born Abid Naseer 24, who was arrested by Scotland Yard detectives in north-east England yesterday.
The former construction site worker is the suspected ringleader of a thwarted plot to bomb targets in Manchester city centre.
He was bound by a control order and electronically tagged after a bid to put him on trial in Britain was aborted last year.
A Government bid to deport him was then controversially blocked by a judge who said his safety in Pakistan could not be guaranteed.
Naseer faces extradition to the United States to go on trial over claims he exchanged coded emails with al Qaida leaders pulling the strings.
He was one of 12 men arrested in April last year during raids in Liverpool and Manchester, known as Operation Pathway.
Naseer is accused of travelling to Pakistan in September 2008 and conducting reconnaissance to prepare for the attack.