WikiLeaks founder Julian Assange mounted a final UK legal challenge on Tuesday to prevent his extradition to the US on spying charges.
His lawyers argued that American authorities are seeking to punish him for exposing serious criminal acts by the US state.
American prosecutors want to put Mr Assange, 52, on trial on 18 counts relating to the release by WikiLeaks of vast troves of confidential US military records and diplomatic cables. They argue the leaks put the lives of US agents in danger and there is no excuse for his criminality.
Mr Assange himself was not in court because of an illness.
His lawyer Edward Fitzgerald said there was a risk that Mr Assange “will suffer a flagrant denial of justice” if he is sent to the US.
At the two-day High Court hearing, his lawyers are asking judges to grant a new appeal, his last legal roll of the dice in Britain.
"Mr Assange is being prosecuted for engaging in ordinary journalistic practices of obtaining and publishing classified information which is true and of public interest," Mr Fitzgerald, Mr Assange's lead lawyer, told the court.
He said, if convicted, Mr Assange could be given a sentence as long as 175 years, and likely to be at least 30 to 40 years.
Another lawyer, Mark Summers, said there was also evidence that there had been a "truly breathtaking plan" to kidnap or murder Mr Assange while he was in the Ecuadorean embassy in London, and former US president Donald Trump had asked for "detailed options" to kill him.
"Senior CIA officials requested plans, the president himself requested on being provided with options on how to do it and sketches were even drawn up," the lawyer said.
Protesters gathered outside the Royal Courts of Justice in London before the hearing. Hundreds of golden ribbons with the words "Free Julian Assange now!" were tied to the main fence and the surrounding gates and trees.
Mr Assange’s wife, Stella, compared his case to that of Alexei Navalny, the Russian opposition activist who died in prison on Friday while serving a three-decade sentence.
"Julian is a political prisoner and his life is at risk. What happened to Navalny can happen to Julian," she told reporters outside court where a large crowd called for his release.
If Mr Assange wins this case, a full appeal hearing will be held to again consider his challenge.
If he loses, his only remaining option would be at the European Court of Human Rights and Mrs Assange said his lawyers would apply to the European judges for an emergency injunction if necessary.
WikiLeaks first came to prominence in 2010 when it published a US military video showing a 2007 attack by Apache helicopters in Baghdad that killed a dozen people, including two Reuters news staff.
It then released thousands of secret classified files and diplomatic cables that laid bare often highly critical US appraisals of world leaders.
His supporters include Amnesty International, media groups and politicians including Australian Prime Minister Anthony Albanese, who last week voted in favour of a motion calling for his return to Australia.
