The driver involved in one of Australia’s most tragic bus accidents has failed in his attempt to have his prison sentence reduced for a catastrophic crash.

Brett Andrew Button, aged 60, received a lengthy prison term for his role in a crash that claimed the lives of 10, predominantly young wedding attendees, and left 25 others injured in June 2023.

Investigations revealed that Button was speeding and under the influence of the opioid Tramadol when his bus overturned at a roundabout in Greta, located in the NSW Hunter Valley.

The judge overseeing his sentencing remarked that in his extensive career in the judicial system, he had never encountered a case with such widespread and devastating consequences.

Among the victims, seven hailed from the nearby town of Singleton, with several connected to the local AFL club. This included coach Nadene McBride, her daughter Kyah, and Kyah’s partner.

Others lived in Queensland or the married couple’s childhood city of Melbourne.

Button appealed the length of his 32-year sentence, with his lawyer arguing some of the 35 criminal charges he pleaded guilty to had been double-counted.

The NSW Court of Criminal Appeal dismissed his appeal on Friday, leaving in place the full term and 24-year non-parole period.

Button’s lawyer had argued the sentence was disproportionate to the crime.

“As catastrophic as the consequences were of the applicant’s dangerous driving, the aggregate sentence imposed was manifestly unjust and unfair,” Button’s barrister Paul Rosser KC had written in submissions to the court.

Button also argued the sentencing judge erred by finding the bus driver knew he was under the influence of the painkiller and that the tipping point of the bus was only 31km/h.

The bus driver had previously argued he did not realise he was affected by the opioid because he had taken it for so long and never felt impacted by it.

Director of Public Prosecutions Sally Dowling SC told the appeal hearing Button should have known he was under the drug’s effect because he was fired from a previous job when his employer learned he had become addicted.

The bus, which was carrying guests from a wine estate wedding, entered an elliptical roundabout on the way to Singleton before tipping over and hitting a guardrail.

“This next part’s going to be fun,” Button told passengers before accelerating into the roundabout and speeding around the turn before the crash.

Survivors described feeling they were about to die as the bus fell sideways towards a roadside barrier.

“The sensation of falling sideways and being completely powerless was terrifying,” Jason Junkeer told Button’s sentencing hearing.