Julian Assange has become so severely ill, he could barely hold a conversation, his lawyers have revealed after the WikiLeaks co-founder failed to front a London court for a hearing on the US request for his extradition.

Just seven weeks into Assange’s 50-week sentence for breaching UK bail conditions, defence lawyer Per Samuelson said it was “impossible to conduct a normal conversation with him”.

His health has deteriorated to the point that he was physically unable to appear via video link for a five-minute extradition hearing at Westminster Magistrates’ Court on Thursday.

Chief magistrate Emma Arbuthnot postponed the hearing until June 12 after referring to Assange as “not very well”.

She said the June hearing will most likely take place at the Belmarsh prison where Assange is located, adding that “it may be more convenient for everyone if it’s there”.

The public gallery was filled with Assange supporters, with many having queued outside the court building for more than an hour.

Just a few hours before the case management hearing, WikiLeaks said it had “grave concerns about the state of health of our publisher, Julian Assange, who has been moved to the health ward of Belmarsh prison”.

WikiLeaks has grave concerns about the state of health of our publisher, Julian Assange, who has been moved to the health ward of Belmarsh prison. – See full statement: pic.twitter.com/HnZVks4kWj

— WikiLeaks (@wikileaks) May 29, 2019

A spokesman added: “During the seven weeks in Belmarsh his health has continued to deteriorate and he has dramatically lost weight. The decision of the prison authorities to move him into the health ward speaks for itself.

“We strongly condemn the refusal by the Swedish court to postpone a hearing on 3rd June on the basis of Mr Assange’s health condition.

“Defence lawyer for Assange, Per Samuelson, said that Assange’s health state last Friday was such ‘that it was not possible to conduct a normal conversation with him’.”

Police arrested Assange on April 11 while at the Ecuadorian Embassy in London where he had been holed up for nearly seven years to avoid extradition to Sweden over a sexual assault case that has since been dropped.

He is currently facing US federal conspiracy charges over allegations he conspired to break into a classified government computer at the Pentagon.

The US Justice Department has indicted Assange on 18 counts that relate to his “alleged role in one of the largest compromises of classified information in the history of the United States”, it said.

He is accused of working with former US army intelligence analyst Chelsea Manning in “unlawfully obtaining and disclosing classified documents related to the national defence”, a statement said.

Also this month, an investigation into rape allegations against Assange, which he denies, has been reopened by Swedish prosecutors who have requested Uppsala District Court detain him in his absence.

Deputy director of public prosecution Eva-Marie Persson said if the court decides to detain Assange, she “will issue a European Arrest Warrant concerning surrender to Sweden”.

Assange supporter and Bafta-winning documentary maker John Pilger said all media organisations are now “in grave danger”.

He told the Press Association outside court: “Every journalist should be here.

“What’s happening to Julian Assange may certainly, almost certainly, happen to many other journalists.

“Today Julian Assange, tomorrow the Press Association, if it prints the truth, the New York Times, the Guardian, all the rest of them.

“If they really do journalism they’re in grave danger at the moment.”

-with AAP