The foreign secretary has branded a UN panel's ruling calling for Julian Assange to be allowed to go free "ridiculous", as the Wikileaks founder demanded the decision be respected.
Mr Assange - who faces extradition to Sweden over a rape claim, which he denies - claimed asylum in London's Ecuadorean embassy in 2012.
The panel said he had been "arbitrarily detained" and should get compensation.
Philip Hammond rejected the decision, accusing Mr Assange of evading justice.
Mr Assange read a statement to the media via a video link
Mr Assange hailed it a "significant victory" and called the decision "binding".
The UN panel ruled Mr Assange was being "arbitrarily detained" in the UK since he was initially arrested in 2010.
A 'significant victory'
Reading a statement via a video link from the embassy, he said the opinion of the panel was "vindication", adding: "The lawfulness of my detention is now a matter of settled law."
Mr Assange said it was a "really significant victory that has brought a smile to my face".
Mr Hammond said Mr Assange was a "fugitive from justice", adding that he can come out "any time he chooses" but will still have to face justice in Sweden.
However, Mr Assange said the comments by Mr Hammond were "beneath" the minister's stature and "insulting" to the UN.
The UK Foreign Office said the report "changes nothing" and it will "formally contest the working group's opinion".
The Met Police said it will make "every effort" to arrest Mr Assange should he leave the embassy.
The government said the panel's ruling was not legally binding in the UK and a European Arrest Warrant remained in place - meaning the UK continued to have a legal obligation to extradite Mr Assange.
The UN's Working Group on Arbitrary Detention insisted Mr Assange's detention "should be brought to an end, that his physical integrity and freedom of movement be respected".
The Wikileaks founder had been subjected to "different forms of deprivation of liberty" it said, initially while he was held in isolation at London's Wandsworth Prison for 10 days in 2010.
The deprivation had been "continuous" since he was initially arrested in the UK on 7 December 2010.
"Mr Assange should be afforded the right to compensation," it added.
Three members of the five-person panel found in Mr Assange's favour, while one rejected his claim and another did not take part in the investigation.
Mr Assange was originally arrested in London in 2010 under a European Arrest Warrant issued by Sweden over rape and sexual assault claims.
In 2012, while on bail, he claimed asylum inside the Ecuadorean embassy in Knightsbridge after the UK Supreme Court had ruled the extradition against him could go ahead.
