Lawyers for the US questioned the frailty of Julian Assange’s mental health on Wednesday as they started a new legal effort to secure his extradition from London to face espionage charges. A British judge ruled in January that the WikiLeaks founder was likely to kill himself if he was held in harsh prison conditions and refused the request to send him to the US where he faces up to 175 years in prison if found guilty. The US told London’s High Court that Mr Assange, 50, had orchestrated one of the “largest thefts of data in history” and called for a rigorous reappraisal of his condition given the “extraordinary lengths” he took to avoid appearing before a court. He was arrested in 2010 at the request of Sweden, which wanted to question him about allegations of rape and sexual assault made by two women. Two years later, Mr Assange jumped bail and sought refuge inside the Ecuadorean embassy in London, where he remained holed up for the next seven years. He was arrested when Ecuador withdrew his asylum and has remained in a British prison since then for bail offences and while he fights the latest extradition request. Mr Assange, an Australian, listened to proceedings by video link from London’s top-security Belmarsh prison. Speaking outside the court, his partner, Stella Moris, described him as an "innocent man accused of practising journalism". "For every day that this colossal injustice is allowed to continue, Julian's situation grows increasingly desperate," Ms Moris, who has two young children with Assange, told reporters. A group of protesters, including Jeremy Corbyn, the former leader of Britain's opposition Labour Party, held placards reading "Journalism is not a crime" and shouted "Free Julian Assange" to the beat of a drum as police looked on. Mr Assange faces 17 espionage charges and one charge of computer misuse over the publication of thousands of leaked military and diplomatic documents a decade ago. But the extradition request was refused after experts warned that Mr Assange displayed autistic and depressive traits. They said he could harm himself, particularly if he was sent to a top-security Colorado jail to serve any sentence. The US, however, said it would agree to him being transferred to an Australian jail if convicted. It said his case was largely based on "his unlawful involvement" in the theft of the diplomatic cables and military files by US Army intelligence analyst Chelsea Manning. Supporters say he was acting as a journalist and deserves freedom of speech protections for publishing documents that exposed US military wrongdoing in Iraq and Afghanistan.