Julian Assange has been denied permission to appeal against the High Court decision to extradite him to the United States, the Supreme Court has confirmed.
On Monday, the UK's highest court said that senior judges had refused Assange's bid to challenge the decision as his application did not raise "an arguable point of law".
However, Assange's legal team previously said there were other parts of his appeal that had not yet been heard by the High Court.
Assange, 50, is wanted in America over an alleged conspiracy to obtain and disclose national defence information following WikiLeaks' publication of hundreds of thousands of leaked documents relating to the Afghanistan and Iraq wars.
US authorities brought a High Court challenge against a January ruling by then-district judge Vanessa Baraitser that Assange should not be sent to the US, in which she cited a real and "oppressive" risk of suicide.
After a two-day hearing, the Lord Chief Justice Lord Burnett, sitting with Lord Justice Holroyde, ruled in favour of the US last year.
The senior judges found that Judge Baraitser had based her decision on the risk of Assange being held in highly restrictive prison conditions if extradited.
However, the US authorities later gave assurances that Assange would not face those strictest measures either pre-trial or post-conviction unless he committed an act in the future that required them.
Lord Burnett previously said that if the original judge had been given those assurances at the time of her ruling, "she would have answered the relevant question differently".
The WikiLeaks founder's lawyers had sought to appeal against that decision at the Supreme Court, arguing it raises "serious and important" legal issues.
In January, Lord Burnett, sitting with Lord Justice Holroyde, refused permission for the appeal, adding that the decision of whether to hear the appeal was up to the Supreme Court.
In her January 2021 ruling blocking the extradition, Judge Baraitser found in favour of the US on all issues except Assange's mental health.
Assange has previously indicated that he wants to challenge the original judge's other findings.