Australia's most-decorated living soldier Ben Roberts-Smith has lost a historic defamation case against three newspapers that accused him of war crimes in Afghanistan.

The outlets were sued over articles alleging he killed unarmed prisoners.

The civil trial was the first time a court has assessed accusations of war crimes by Australian forces.

A judge said four of the six murder allegations - all denied by the soldier - were substantially true.

These included:

Justice Anthony Besanko found the newspaper had not proven two other murder allegations; nor reports Mr Roberts-Smith had assaulted a woman with whom he was having an affair; nor a threat against a junior colleague.

But additional allegations that he had unlawfully assaulted captives and bullied peers were found to be true.

Mr Roberts-Smith, who left the defence force in 2013, has not been charged over any of the claims in a criminal court, where there is a higher burden of proof. The 44-year-old was not present for Thursday's judgement.

After the decision, a Taliban spokesman said the case was proof of "uncountable crimes" by foreign forces in Afghanistan, but added he did not trust any court globally to follow them up.

Australian troops were deployed to Afghanistan between 2001 and 2021. Australian Defence Minister Richard Marles declined to comment on the case, saying it was a civil matter.

Mr Roberts-Smith is Australia's most famous living war veteran and served with the country's elite Special Air Service Regiment (SAS).

He received the country's highest military award - the Victoria Cross - in 2011 for having single-handedly overpowered Taliban machine-gunners who had been attacking his platoon.

But his public image was shattered in 2018 when The Sydney Morning Herald, The Age and The Canberra Times started publishing articles about his misconduct between 2009 and 2012.

The soldier argued five of the killings reported by the newspapers had occurred legally during combat, and the sixth did not happen at all.

His defamation case - dubbed by some "the trial of the century" - lasted 110 days and was rumoured to have cost up to A$25m ($16.3m, £13.2m).

More than 40 witnesses - including Afghan villagers, a government minister and a string of current and former SAS soldiers - gave extraordinary evidence about every facet of Mr Roberts-Smith's life.

But the case also exposed some of the secretive inner workings of Australia's elite special forces.

The trial heard from soldiers who said potential misconduct was rarely reported due to a "code of silence" within the regiment, and others defended their actions as necessary.

Many giving evidence were there unwillingly, having been subpoenaed, and three refused to speak about some allegations fearing self-incrimination.

Much of the evidence against Mr Roberts-Smith relied on eyewitness accounts and recollections of discussions among soldiers. Justice Besanko had to weigh the reliability of witnesses against each other, with the media outlets contending theirs had no reason to lie.

Speaking outside the Federal Court in Sydney, the news outlets called the judgement a "vindication" for their reporting.

"It's a day of justice for the brave men of the SAS who stood up and told the truth about who Ben Roberts-Smith is: a war criminal, a bully and a liar," said investigative reporter Nick McKenzie, who wrote the stories alongside Chris Masters and David Wroe.

"[And] today is a day of some small justice for the Afghan victims of Ben Roberts-Smith."

The Afghanistan Human Rights and Democracy Organisation also praised the role of investigative journalism in "uncovering the truth and raising public awareness" about what had taken place in the country.

Media magnate Kerry Stokes - who employs Mr Roberts-Smith at rival outlet Seven West Media - said the judgement did "not accord with the man I know".

"I know this will be particularly hard for Ben, who has always maintained his innocence," said Mr Stokes, who loaned the soldier money to fund his legal case. Mr Roberts-Smith had offered to hand in his Victoria Cross as collateral, local media reported.

The case comes three years after a landmark report found credible evidence that Australian forces had unlawfully killed 39 civilians and prisoners in Afghanistan from 2007 to 2013.

Accusations of war crimes have also been levelled at soldiers from the UK and US in recent years.

Local media say dozens of Australian soldiers are being investigated for their roles in alleged war crimes. But so far charges have only been laid against one, Oliver Schulz.

War historian Peter Stanley told the BBC ahead of the judgement that Mr Roberts-Smith's case was "a litmus test" for allegations of Australian wrongdoing in Afghanistan.

"The Ben Roberts-Smith episode is just a precursor to the major series of war crimes investigations, allegations, prosecutions, and possibly convictions that we'll see over the next few years."