An Algerian man wanted in connection with a series of Paris train bombings in 1995 must be extradited to France, Home Secretary Charles Clarke says.
Eight people died in the Metro attack in 1995
Rachid Ramda, 35, who has spent 10 years in UK jails, must be surrendered to the French, Mr Clarke ruled.
He is accused of conspiring in an explosion which killed eight people in a Paris Metro station, and organising and financing several other bombings.
Mr Ramda's solicitors are expected to apply for a judicial review.
If the review is successful, his extradition could be delayed even further.
Mr Ramda faces 23 charges of financing and organising a bombing campaign in France between August and November 1995.
On a separate extradition request, he is accused of being a conspirator in the bombing of the Saint Michel Metro station on 25 July 1995, in which eight people were killed and 87 injured.
He is also believed to be a financier of Algeria's outlawed Armed Islamic Group (GIA).
The GIA, which fights the government in Algeria, is thought to be responsible for the 1995 bombing campaign.
Mr Ramda is already thought to be the UK's longest-serving extradition prisoner.
In 2001 David Blunkett, then home secretary, ordered his extradition.
But the High Court overturned Mr Blunkett's decision the following year.
Since then his case has been under review, culminating in the decision taken by Mr Clarke on 6 April this year - but not made public.
A Home Office spokesman said: "The home secretary has ordered the surrender of Rachid Ramda to the French authorities.
"He stands accused by the French of involvement in serious terrorist activities."
The spokesman said he expected Mr Ramda's solicitors to ask for a judicial review at the High Court.