WikiLeaks founder Julian Assange was warned by the judge in his extradition case that he would be removed from court if he continued to interrupt witnesses.
The judge, Vanessa Baraitser, told the 49-year-old that he would face being permanently banned from hearings.
The incident took place as a lawyer for the US questioned the expertise of witnesses who appeared on behalf of Assange.
The WikiLeaks founder faces allegations that he conspired with computer hackers to encourage them to obtain secret US government documents, after being re-arrested this week.
The allegations were added, in a superseding indictment, to 17 charges under the 1917 Espionage Act related to WikiLeaks publishing a series of leaks from Chelsea Manning, a former US Army soldier turned whistleblower, in 2010-11.
The hearing revealed differences between the defence lawyers over the charges levelled against Assange in the US indictment.
Speaking on the second day of the hearing at the Old Bailey, Clifford Stafford Smith, founder of legal support non-profit organisation Reprieve, told the court that the charity had used US cables leaked by WikiLeaks in its cases.
He gave evidence on WikiLeaks’ publication of the Afghan and Iraq War Logs, the Guantanamo Files, and the US diplomatic cables.
He said WikiLeaks disclosures on drone killings had contributed to a sea change in people’s attitudes about the use of drones.
“I feel my country’s reputation was seriously damaged by what we have to term as criminal actions,” he said.
He said one US journalist, Bilal Abdul Kareem – who reported from Syria on the struggle against the regime of its president, Bashir Assad – had been targeted for assassination five times, including hellfire missiles from drones.
An ongoing case is testing whether the US has the right to assassinate its own citizens. “I find it deeply troubling,” he said.
Reprieve had uncovered evidence that individuals detailed at Guantanamo Bay were not being held for terrorism reasons, but because the US had paid bounties for them.
Pervez Musharraf, former president of Pakistan, boasted in his book In the line of fire that perhaps half of the Guantanamo detainees had been sold for bounties to the US by Pakistan. “They were sold with a story – normally, in my experience, bogus – to induce payment,” Stafford Smith said in a witness statement.
“I felt that Guantanamo was doing our nation damage. I thought, by and large, the government would make some mistakes, but would get it right. I was wrong,” he told the court.
He said WikiLeaks leaks on Guantanamo had been important in making public allegations against clients he was representing in the detention camp.
“They were the very worst that the US authorities could confect against our clients, but on the other hand they are very important because the world did not know the allegations against my clients,” he said.
In a witness statement, Stafford Smith said he had taken 30 pages of evidence from his client Moazzam Begg on how he was tortured and how he had witnessed a murder at Bagram Air Force Base in Iraq.
The statement was censored because torture and murder reflected “methods and means of interrogation”.
“I would never believe that my government would do what it did,” he said. “We are talking about criminal offences of torture, rendition, holding people against the law and, I am sad to say, murder.”
The WikiLeaks documents referred to statements about another of Stafford Smith’s clients, Binyam Mohamed, as if they were true, without mentioning the fact he was rendered to Morocco for 18 months “where the interrogators took a razor blade to his genitals”, Stafford Smith said in written evidence
A UK court found that the UK had been “mixed up” in Mohamed’s torture.
The UK intelligence agencies leaked Mohamed’s statement, obtained under torture, to the BBC.
Stafford Smith told the court that it was only because he was at the BBC that he was able to prevent the journalist from using the statement, which had been obtained in violation of the UN Convention Against Torture.
James Lewis, representing the US, told the court that Stafford Smith had produced a 97-paragraph statement, but did not mention WikiLeaks until paragraph 31.
“Would it surprise you to learn that there are no charges against Mr Assange or anyone else for publishing those cables or any cables you mention in your statement?”
Lewis said the only thing Assange was being charged with was leaking documents that put the names of individuals in Iran, Afghanistan and around the world, who were at risk.
Stafford Smith said that in a US court case, the US could produce a witness that could give wide-ranging testimony.
“Mr Stafford you are making this up. Show me where the charges show the publication of documents,” said Lewis.
Stafford Smith said: “I can tell you how American cases are prosecuted.”
Lewis then asked Stafford Smith: “Are you saying the US Attorney General is lying?”
Stafford Smith said that the most damaging thing he had seen during his 19 years was over-classification by US officials.
He said that Begg, who was detained in Guantanamo, had given him 30 pages of material on how he had been tortured, but it was classified for national security reasons. “That over-qualification, where we classify evidence of torture, is profoundly wrong.”
Stafford Smith said he accepted that it was not right to put informants in harm’s way.
Lewis referred to a book written by investigative journalist David Leigh. Leigh was concerned that many of the documents obtained by WikiLeaks mentioned informants.
Assange’s response, as reported in the book, was: “If they get killed, they deserve it.”
Stafford Smith said: “I really would never judge someone by what is published in a book. I agree you should never get someone killed.”
Lewis said the charges against Assange only related to a small number of documents published by WikiLeaks.
Stafford Smith said he did not have that confidence in US court cases, and that the US could introduce new allegations against Assange.
“They could potentially, through their first witness, introduce the book by David Leigh, and the rules of hearsay have a massive lacuna in it. I wish I had your confidence,” he said.
The judge adjourned the hearing after Assange interrupted Stafford Smith.
“’If you interrupt proceedings, it is open to me to proceed in your absence. This is obviously something I would not wish to do,” she said.