Julian Assange has been told he can seek permission from the Supreme Court to challenge his extradition to the US on espionage charges.
The WikiLeaks founder, 50, is appealing against a High Court decision in December which had overturned a ruling that he should not be extradited due to risk of suicide.
He is wanted in the US on a string of criminal charges linked to a vast leak of sensitive military documents that were published on the WikiLeaks website.
On Monday, Lord Chief Justice Lord Burnett, sitting with Lord Justice Holroyde, delivered a short verbal ruling saying Assange must seek permission from the Supreme Court for an appeal.
For a proposed appeal to be considered by the UK's highest court, a case has to raise a point of law of "general public importance".
The judges ruled on Monday there was a point of law, but denied him permission for the appeal.
However, the Lord Chief Justice said Assange could go to the Supreme Court itself and ask to bring the appeal.
"Whether or not the issue needs ventilation in that court is a matter appropriately for its decision," Lord Burnett said.
In December, US authorities argued at a hearing in London that the decision of District Judge Vanessa Baraitser earlier that year risked "rewarding fugitives for their flight".
James Lewis QC, for the US government, said the lower court had been mistaken for viewing as a "trump card" Mr Assange's "intellectual ability" to overcome suicide prevention measures in an American jail.
The US has also assured Britain that, if convicted, Mr Assange will be able to serve his sentence in Australia, his home country, and pledged he would not face detention under harsh conditions in a so-called 'supermax' prison.
