Wikileaks founder Julian Assange’s extradition to the US has been approved by UK Home Secretary Priti Patel.
Mr Assange has 14 days to appeal over the decision, the Home Office said.
It said the courts found extradition would not be "incompatible with his human rights" and that while in the US "he will be treated appropriately".
Mr Assange is wanted by the American authorities over documents leaked in 2010 and 2011, which the US says broke the law and endangered lives.
The Wikileaks documents related to the Iraq and Afghanistan wars.
The Australian is being held at Belmarsh prison in London after mounting a lengthy battle to avoid being extradited.
Extradition allows one country to ask another to hand over a suspect to face trial.
Responding to the home secretary's order, Wikileaks confirmed it would appeal against her decision.
Mr Assange's wife, Stella, said her husband had done "nothing wrong" and "he has committed no crime".
"He is a journalist and a publisher, and he is being punished for doing his job," she said.
Media company Wikileaks is a whistle-blowing platform that publishes classified material provided by anonymous sources.
This decision is the most important stage so far in Mr Assange's long legal battle.
Judges in London have already ruled that the US's request was lawful and that the American authorities would care for him properly in prison.
Now, the home secretary has carried out her role in the complicated legal process by signing off the US request.
Her officials said she was legally bound to do so because Mr Assange does not face the death penalty - nor does his case fall into the other narrow range of categories for her to refuse to approve the transfer.
In practice, this means there is nothing to stop Washington sending a jet to pick up Mr Assange - unless he can win on appeal.
If his lawyers cannot get a hearing back before judges in London, he could petition the European Court of Human Rights.
Ten years ago it ruled extradition to the US would not breach human rights - but expect the Wikileaks founder to try fresh arguments not heard back then.
