WikiLeaks founder Julian Assange should be allowed to walk free immediately and compensated for his "arbitrary detention" of over five years by the UK and Sweden, a UN panel ruled today, a finding hailed by the whistleblower as "vindication" of his innocence.

The Geneva-based five-member Working Group on Arbitrary Detention "considers that the various forms of deprivation of liberty to which Julian Assange has been subjected constitute a form of arbitrary detention," said Seong-Phil Hong, head of the expert panel of the Group.

"The Working Group maintains that the arbitrary detention of Mr. Assange should be brought to an end, that his physical integrity and freedom of movement be respected, and that he should be entitled to an enforceable right to compensation," Hong added. Assange told reporters via video link from the Ecuadorean embassy building in central London, where he has been holed up, that "it is now the task of the states of Sweden and the United Kingdom as a whole to implement the verdict", which he hailed as "vindication" of his innocence.

Assange's lawyer Melinda Taylor also called the ruling "a resounding vindication of Mr. Assange's position". The computer hacker, who founded the WikiLeaks in 2006 that released 500,000 secret US military files on the wars in Afghanistan and Iraq and 250,000 diplomatic cables enraging Washington, has been confined to a small in the embassy to avoid extradition to Sweden to face a rape investigation.

However, both Sweden and the UK rejected the non-binding legal opinion, saying it "changes nothing". The UK said it will formally contest the opinion, which Foreign Secretary Philip Hammond termed as "ridiculous" while Sweden said the panel had no right to "interfere".