Wikileaks founder Julian Assange has won the right to petition the UK Supreme Court in his fight against extradition to Sweden.
He lost a High Court battle last month to be extradited over alleged sex offences, which he denies.
Judges refused Mr Assange permission to appeal directly to the Supreme Court - but said his case raised "a question of general public importance".
He can now directly ask the Supreme Court to look at his case.
However, Mr Assange, who was at the London court to hear the judges' ruling, still has no automatic right to be heard by the highest court in the UK.
He was cheered by supporters as he left the Royal Courts of Justice and, alluding to an MPs' debate later on calls for the renegotiation of extradition rules, he said there were "many aggrieved families in the UK and other countries and in Europe struggling for justice".
Speaking of his own case, he said: "I think that is the correct decision, and I am thankful. The long struggle for justice for me and others continues."
Mr Assange, 40, is founder of the whistleblowing website Wikileaks, which has angered the United States by releasing hundreds of thousands of classified US documents.
The Australian faces extradition over accusations he raped a woman and sexually molested another in Stockholm in August last year. He denies the allegations.
Mr Assange was arrested in London a year ago on a European Arrest Warrant (EAW) and has been living at the country estate of a supporter under stringent bail conditions. He claims his arrest was politically motivated and linked to the activities of Wikileaks.
District Judge Howard Riddle ruled in February that Mr Assange should be extradited to face investigation following a hearing at City of Westminster Magistrates' Court in central London. The decision was upheld at the High Court last month.
Mr Assange attempted to appeal the decision on two grounds.
He argued the highest court should consider whether his extradition would be unlawful because the request was made by a "partisan prosecutor working for the executive" and whether he could be defined as "the accused" even though no decision has been taken to prosecute him.
'Quickly as possible'
On Monday the High Court certified that the case raised the question of whether the Swedish prosecutor who issued the EAW against Mr Assange was a "judicial authority". Mr Assange's lawyers argue the prosecutor was not, and the warrant was therefore invalid.
Mark Summers, appearing for Mr Assange, said: "Public prosecutors should not, in any circumstances, be permitted to issue EAWs."
One of the two judges, Sir John Thomas, told Mr Summers the court's view was that it had "very little doubt that, as a matter of law, the prosecutor was within the scheme" for issuing warrants, and Mr Assange's chances of success in the Supreme Court were "extraordinarily slim".
But the judge said the court felt "constrained" to certify that the case raised a question of general public importance.
However, it would be left to the Supreme Court to decide whether to give Assange actual leave to appeal, it was ruled.
Sir John said: "If leave is granted by the Supreme Court we would, for obvious reasons, ask that the point is decided as quickly as possible."
Outside the court Mr Assange's lawyer, Gareth Peirce, said his legal team had 14 days to submit a written petition to the Supreme Court.
She told reporters that if the court refused to hear the request then Mr Assange would have exhausted all legal avenues in Britain.