An order to extradite Julian Assange to the US to face espionage charges has been signed by UK Home Secretary Priti Patel.
The Wikileaks founder is wanted in the US over the mass leak of classified documents in 2010 and 2011.
Mr Assange has 14 days to appeal the decision, which was passed to the Home Secretary after consideration by Westminster Magistrates Court and the High Court.
The Australian, who has been battling extradition for more than a decade, is being held at Belmarsh prison in London.
A Home Office spokesperson said: "On 17 June, following consideration by both the Magistrates Court and High Court, the extradition of Mr Julian Assange to the US was ordered.
"Mr Assange retains the normal 14-day right to appeal.
"In this case, the UK courts have not found that it would be oppressive, unjust or an abuse of process to extradite Mr Assange.
"Nor have they found that extradition would be incompatible with his human rights, including his right to a fair trial and to freedom of expression, and that whilst in the US he will be treated appropriately, including in relation to his health."
A WikiLeaks spokesman said: "This is a dark day for press freedom and for British democracy.
"Anyone in this country who cares about freedom of expression should be deeply ashamed that the Home Secretary has approved the extradition of Julian Assange to the United States, the country that plotted his assassination.
"Julian did nothing wrong. He has committed no crime and is not a criminal. He is a journalist and a publisher, and he is being punished for doing his job.
"It was in Priti Patel's power to do the right thing. Instead she will forever be remembered as an accomplice of the United States in its agenda to turn investigative journalism into a criminal enterprise."
