A judge has refused to release Julian Assange from prison over the coronavirus outbreak.

The Wikileaks founder’s lawyers had applied for him to be freed on bail because he was “vulnerable” to the virus inside HMP Belmarsh.

He is being held there while awaiting potential extradition to the US on charges relating to the 2010 Wikileaks publications over the Iraq and Afghanistan wars.

Mr Assange at Westminster Magistrates’ Court by video-link on Wednesday and was represented by Edward Fitzgerald QC, who wore a surgical mask.

The court heard that despite coronavirus being confirmed in other jails, there were not yet an known cases in HMP Belmarsh.

But Mr Fitzgerald said that 100 prison officers were off work, adding: “We say there’s a very real problem, a very real risk and the risk could be fatal.”

District judge Vanessa Baraitser refused the bail application, telling the court: “As matters stand today, this global pandemic does not of itself yet provide grounds for Mr Assange’s release.”

Supporters of Mr Assange said he had a previously reported lung complaint and was in an “already weakened medical condition”.

Kristinn Hrafnsson, editor in chief of Wikileaks, said: “To expose another human being to serious illness, and to the threat of losing their life, is grotesque and quite unnecessary. This is not justice, it is a barbaric decision.”

American and British authorities class Mr Assange as a flight risk because he skipped bail over Swedish sexual assault allegations to flee to London’s Ecuadorian embassy in 2012.

Key moments for Julian Assange Show all 9 1 /9 Key moments for Julian Assange Key moments for Julian Assange The situation today Assange was arrested after Metropolitan Police officers were invited into the Ecuadorian embassy on April 11 2019. How did it come to this? Ruptly TV Key moments for Julian Assange The break Assange shows the front page of the Guardian on July 26 2010, the day that they broke the story of the thousands of military files leaked by WikiLeaks AFP/Getty Key moments for Julian Assange Wanted A warrant for Assange's arrest was issued in August 2010 for counts of rape and molestation in Sweden AFP/Getty Key moments for Julian Assange Ruling The UK's Supreme Court ruled in 2012 that Assange should be extradited to Sweden to face trial Getty Key moments for Julian Assange Sanctuary Following the ruling, Assange was given asylum by the Ecuadorian governement over fears that his human rights would be violated if he were extradited, he has since remained in the embassy in London Getty Key moments for Julian Assange A friend in Pam Friend Pamela Anderson delivers lunch to Assange at the embassy in October 2016. She has since spoken against his arrest Getty Key moments for Julian Assange Arbitrarily detained A UN panel found in 2016 that Assange had been arbitrarily detained and that he had not been able to claim his full right to asylum. It urged Sweden to withdraw the charges against him Getty Key moments for Julian Assange The cat ultimatum Last year, the Ecuadorian embassy threatened to revoke Assange's internet access unless he stopped making political statements online and started taking better care of James, his pet cat. Assange accused Ecuador of violating his rights Reuters Key moments for Julian Assange Arrest Assange was arrested on April 11 2019. Ecuador revoked his asylum status and invited the Metropolitan Police in to the embassy to arrest him. Reuters

That investigation has been dropped, but he is now fighting to avoid being sent to the US to face 17 charges under the Espionage Act and conspiracy to commit computer intrusion after the publication of hundreds of thousands of classified documents.

There are mounting calls for lower-risk inmates to be released from British prisons as coronavirus spreads.

Jails in England and Wales have been put on lockdown, with all visits cancelled.

On Tuesday Jo Farrar, chief executive of the Prison and Probation Service, told the Commons Justice Committee that 13 inmates had tested positive for coronavirus and around 4,300 prison and probation staff were self-isolating.

Mobile phones are being made available to inmates to aid contact with loved ones, following deadly riots over restrictions in Italian prisons.

But gyms have been closed and activities including education and training suspended.

Justice Secretary Robert Buckland told the committee “quite a proportion of the estate where there is crowding – that presents a real challenge” and many inmates were vulnerable or had underlying health conditions.

He did not rule out considering releasing prisoners but said the risks involved would “have to be considered”.