The founder of WikiLeaks is wanted in the United States on espionage charges for leaking military secrets. He will remain in custody in the UK while the appeal goes ahead.

The High Court in London ruled Monday that WikiLeaks founder Julian Assange has a right to appeal against his extradition to the United States.

Assange is facing 17 espionage charges and one charge of computer misuse due to his website’s publication of a trove of classified US documents almost 15 years ago.

Assurances over free speech

Assange has spent the last five years in a British high-security prison after seeking refuge in the Ecuadorian Embassy in London for seven years, trying to avoid extradition.

In 2022, the United Kingdom’s then-Home Secretary, Priti Patel, signed an extradition order, but Assange turned to the High Court in February 2024 to ask for permission to appeal.

In March, two judges rejected the bulk of Assange’s arguments but said he could take his case to the Court of Appeal unless Washington provided further assurances his life would not be at risk and his right to free speech would be infringed.

Assange’s lawyers argued that the US had not guaranteed he would have the same free speech protections as an American citizen if extradited from Britain.

“We say this is a blatantly inadequate assurance,” his lawyer told the court. 

They had accepted a separate assurance that Assange would not face the death penalty. The US had provided an “unambiguous promise not to charge any capital offense.”

On Monday, two senior judges found he has grounds to challenge the UK government’s extradition order.