WikiLeaks founder Julian Assange has failed in his bid to reopen his appeal against extradition to Sweden where he faces sex crime allegations.

The announcement was made today by the Supreme Court.

It is understood that Assange's legal team now has 14 days to apply to the European Court of Human Rights in Strasbourg to hear his case.

Dinah Rose QC, appearing for Assange, applied to the Supreme Court justices for permission to make further submissions, but they unanimously dismissed the application, saying it was "without merit".

On May 30, the Supreme Court ruled by a 5-2 majority that Assange's extradition was lawful and could go ahead.

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, claims the sex was consensual and that the allegations against him are politically motivated.

The majority of Supreme Court justices rejected his argument that the European arrest warrant (EAW) issued against him by Sweden was "invalid and unenforceable".

Assange's lawyers now have until June 28 to ask Strasbourg to consider his case on the basis that he has not had a fair hearing from the UK courts.

It will then be for the European Court to decide whether or not to postpone extradition while another hearing goes ahead

The court has the power to issue a direction to the UK Government that he should not be surrendered to Sweden if it decides to consider his claim.

Fair Trials International chief executive Jago Russell said: "Today's decision takes Julian Assange one step closer to being extradited to Sweden.

"Although Sweden is rightly proud of its justice system, its over-use of pre-trial detention means that, if extradited, he is likely to be imprisoned and placed under extremely restrictive conditions."