WikiLeaks founder Julian Assange will be allowed to appeal his extradition to the U.S. on espionage charges.

At a hearing Monday, two senior judges in London ruled in favor of Assange, who argued he might not be able to rely on the U.S. First Amendment’s right to free speech, per Reuters.

Assange, the founder of WikiLeaks faces 18 charges in the U.S.  regarding the release of secret U.S. documents, considered the largest security breach in U.S. military history.

The Australian-born Assange, 52, was not present at Monday’s hearing, which was for health reasons, his lawyer said.

Cheers of “Free, free Julian Assange” were heard outside the courtroom.

Assange’s wife Stella spoke to him after the ruling and said he was “obviously relieved.”

“We don’t know how long this will go on for and it takes an enormous toll on him,” Stella Assange told Reuters. “I hope that the U.S. administration looks at this case and now … considers it should just be dropped.”

“The signals should be clear that it’s time to drop it,” she said.

The U.S. Justice Department did not comment, citing a pending judicial matter.

If Assange lost Monday, he could have been extradited to the U.S. within 24 hours.

“It could be many months until the appeal is heard, and then that decision could be taken to the UK Supreme Court,” Reuters reported.

Prosecutors in the U.S. previously told the court could rely on First Amendment protections Americans are afforded and he would not face discrimination because of his nationality.

His attorneys were not that confident in the assertion.

“We say this is a blatantly inadequate assurance,” Assange’s lawyer Edward Fitzgerald said.