Signs showing support for WikiLeaks founder Julian Assange are seen in a protest outside the High Court in London, Britain, on March 26, 2024. [Photo/Xinhua]

WikiLeaks founder Julian Assange on Monday won a victory in his ongoing battle against extradition from the United Kingdom (UK) to the United States, after the High Court in London granted him permission to appeal.

Permission to appeal was to be granted only if the U.S. government was unable to provide the court with suitable assurances that Assange can rely on the First Amendment (free speech) for protection.

The U.S. government had to prove that Assange, who is Australian, will not be prejudiced at trial due to his nationality, and will be afforded the same protections as a U.S. citizen.

The U.S. side also had to provide assurance that Assange would not be sentenced to death if convicted.

Assange's legal team criticized the assurances provided by the U.S. government at the hearing, arguing that "based on the principle of the separation of powers, the U.S. court can and will apply U.S. law, whatever the executive may say or do."

Most of the assurances were "blatantly inadequate," said Edward Fitzgerald KC, representing Assange. However, the U.S.' assurance on the death penalty was accepted by Assange's legal team.

The lawyer said in written submissions that while the assurance on the death penalty was "an unambiguous executive promise," the other assurances do not give "any reliable promise as to future action."

Assange supporters cheered at the news of the court's ruling. He was not in court on Monday for health reasons, but those present included his wife Stella.

"The judges reached the right decision... As a family we are relieved, but how long can this go on? The United States should read the situation and drop this case now. Now is the moment to do it. Just abandon the shameful attack on journalists, on the press and on the public," Stella told supporters outside the High Court.

According to Assange's legal team, it could be months before the new appeal is heard.

The latest move came after the High Court deferred a decision in March on whether Assange could take his case to another appeal hearing.

Assange, 52, is wanted by the U.S. for allegedly disclosing national defense information following WikiLeaks's publication of hundreds of thousands of leaked military documents relating to the Afghanistan and Iraq wars a decade ago. These included Apache helicopter video footage of the U.S. military gunning down journalists and children in the streets of Baghdad in 2007.

Assange has been held at southeast London's high-security Belmarsh Prison since 2019. The UK approved his extradition to the U.S. in 2022, after a judge had initially blocked it due to concerns over his mental health. Assange and his lawyers have subsequently appealed.