One of the most significant moments in Australian military history unfolded without fanfare on a tarmac at Sydney airport, when Ben Roberts-Smith was calmly escorted off a plane and into a waiting police car. The country's most-decorated living soldier and the most famous of his generation, Roberts-Smith was on Tuesday charged with five counts of the war crime of murder.

It follows a high-profile civil defamation case, which three years ago found that the former Special Air Service (SAS) corporal and Victoria Cross recipient had unlawfully killed several unarmed Afghan detainees. Roberts-Smith, who left the Australian Defence Force (ADF) in 2013, denies all wrongdoing and says the allegations are egregious and driven by spiteful and jealous peers.

His case – now set to be tested to a higher, criminal standard – has become the face of Australia's reckoning over the country's alleged conduct in Afghanistan, which has cast a pall over its much-mythologised military legacy.

For Roberts-Smith to now be charged with war crimes - and not just one, but multiple war crimes - is a very significant cultural and social moment for a country that, for much of its history… has placed a lot of store in the exploits and contributions of the members of its defence forces, Professor Donald Rothwell told the BBC.

When Roberts-Smith came home from Afghanistan in 2013, he was considered a national hero, having been awarded Australia's highest military honour for single-handedly overpowering Taliban fighters attacking his SAS platoon. Plum speaking engagements and board gigs, magazine covers and massive portraits, accolades and awards – like Father of the Year – followed.

But in 2018, Nine newspapers began publishing a series of articles alleging misconduct during his time with the SAS – claims of unlawful beatings and killings of prisoners, bullying of colleagues, and domestic violence against a mistress. He said it was all untrue, and in a bid to clear his name, launched a high-profile legal battle, which spanned seven years, cost millions of dollars, and was dubbed by some as Australia's trial of the century.

He lost. A Federal Court judge in 2023 ruled the reports he committed four murders were substantially true, a judgement that was upheld on appeal. Roberts-Smith, now faces even higher stakes if convicted: life in prison, and an unwelcome place in history.

The investigation leading to Roberts-Smith's arrest was conducted by the Office of the Special Investigator (OSI), a specialist unit established following the 2020 Brereton Report, which suggested that Australian special forces unlawfully killed 39 individuals in Afghanistan and recommended further investigations into 19 current or former ADF members.

This unprecedented case raises questions not only about Roberts-Smith's actions but also about Australia's military ethics and the legacy of conflict, marking a pivotal moment in holding military personnel accountable for actions during wartime.