Wikileaks founder Julian Assange will be extradited to Sweden where he faces allegations of sex crimes, the Supreme Court said on Wednesday.
Lawyers for the WikiLeaks founder had asked the UK's highest court to block his removal, arguing that the European arrest warrant issued against him is "invalid and unenforceable".
A panel of seven Supreme Court judges, who heard the case in February, gave their judgment in the marathon battle in the UK courts over the issue on Wednesday.
Assange lost the appeal by 5-2. His lawyers have 14 days to challenge the ruling.
The Swedish authorities want Assange, 40, to answer accusations of raping one woman and sexually molesting and coercing another in Stockholm in August 2010 while on a visit to give a lecture.
Assange, whose WikiLeaks website has published a mass of leaked diplomatic cables that embarrassed several governments and international businesses, says the sex was consensual and the allegations against him are politically motivated.
Solicitor Gareth Peirce, who represents Assange, said after today's hearing: "We are going to ask the Supreme Court to reconsider."
She said the case had raised an important legal issue about the meaning of "judicial authority".
She suggested that MPs had thought that a judicial authority meant a judge rather that a prosecutor when they adopted extradition rules.
Journalist John Pilger, who was at today's hearing to support Assange, said lawyers might also launch a challenge in a European court.
"It's not over," he said. "It could come back here for a hearing. It could go to Europe - or both."
After missing today's formal hand-down of the judgment against him, Assange tweeted: "We got the news not hoped for".