Julian Assange will face a five-day US extradition hearing in February next year, a judge has ruled.

The WikiLeaks founder faces an 18-count indictment, issued by the US Department of Justice, that includes charges under the Espionage Act.

At Westminster magistrates court on Friday, the chief magistrate, Emma Arbuthnot, ordered that a full extradition hearing should begin on 25 February.

Ben Brandon, representing the US, formally opened the case, a day after an extradition request was signed off by the home secretary, Sajid Javid.

“This is related to one of the largest compromises of confidential information in the history of the United States,” Brandon told the court.

As Brandon ran through a summary of the accusations against Assange, including that he had cracked a US defence network password, Assange, appearing by video link, protested: “I didn’t break any password whatsoever.”

Assange, 47, who was dressed in a grey T-shirt, had a white beard and was wearing black-framed glasses, said 175 years of his life was at stake and defended his website against hacking claims, saying: “WikiLeaks is nothing but a publisher.”

His lawyer, Mark Summers QC, described the case as “an outrageous and full-frontal assault on journalistic rights”.

His legal team also said he was challenging the 50-week sentence in Britain for skipping bail he is serving after he spent seven years in the Ecuadorian embassy in London attempting to avoid extradition to Sweden.

Assange is accused in the US of soliciting and publishing classified information and conspiring to hack into a government computer.

Outside the court, his supporters protested against the UK’s treatment of him. A crowd of around a dozen people held banners, with some chanting “Justice for Julian Assange” and “Defend freedom and democracy.”