The British government requested permission on Wednesday to take its long-running legal fight to deport radical preacher Abu Qatada to the highest court in the land.
The move to appeal to the Supreme Court comes after judges last month rejected the latest attempt to remove the terror suspect to Jordan, where he was convicted in his absence of terrorism charges.
In March, Court of Appeal judges backed an earlier ruling that Abu Qatada, also known as Omar Othman, could not be deported over fears that evidence obtained through torture would be used against him in a retrial.
The Court of Appeal made that ruling despite acknowledging that ministers believe the 52-year-old to be "an exceptionally high-risk terrorist".
A spokesman for the Home Office, or interior ministry, said: "We have today asked the Court of Appeal for permission to appeal its recent decision on Abu Qatada to the Supreme Court.
"The government remains committed to deporting this dangerous man and we continue to work with the Jordanians to address the outstanding legal issues preventing deportation."
The government has now been trying to deport Abu Qatada to Jordan for nearly eight years.
Lawyers for Home Secretary Theresa May challenged a ruling made in November by immigration judges on the grounds that Qatada had escaped deportation through "errors of law".
But three Court of Appeal judges said the Special Immigration Appeals Commission (Siac) had grounds to conclude that disputed statements would be used against him in Jordan.
Abu Qatada, who featured in hate sermons found on videos in the flat of one of the 9/11 bombers, first arrived in Britain in 1993 claiming asylum.
He was taken back to jail last month after he was arrested for alleged bail breaches.
A hearing over whether he should be granted bail again was due to be held last month but was delayed.
Police searched the hate preacher's family home in London before he was detained and said afterwards he is being investigated over extremist material.