Radical cleric Abu Hamza has launched a last-minute appeal to the high court to block his extradition to the US to face terrorism charges.
The application comes after the European Court of Human Rights rejected a bid by Hamza and four other terrorism suspects to halt their cases.
A second suspect, Khaled al-Fawwaz, has also mounted an appeal against been sent to the US for trial.
Hamza, who was jailed for seven years for soliciting murder and inciting racial hatred, has been fighting extradition since 2004. The suspects argued that they would face inhumane treatment in the US.
The Home office said the latest appeal was nothing more than a delaying tactic as the men have exhausted all lines of action.
A Home Office spokesperson said: "The European Court of Human Rights ruled there was no bar to the extradition of these men. We will continue working to ensure they are handed over to the US authorities as soon as possible."
It is not known on what grounds the appeal was launched. A date has not yet been set for the hearing.
Two other suspects, Babar Ahmad and Syed Tahla Ahsan, are accused of running a pro-jihadi website and could face a private prosecution in Britain. That could take precedent over any US trial.
Hamza, who claims to have lost an eye and hand fighting the Soviet occupation of Afghanistan in the 1980s, used London's Finsbury Park Mosque as a base to persuade young Muslims to take up the cause of holy war.
The mosque was once attended by 9/11 conspirator Zacarias Moussaoui and "shoe bomber" Richard Reid.