Allison Baden-Clay’s longtime friend has expressed her “relief and elation” over the High Court’s decision to reinstate Gerard Baden-Clay’s conviction for murdering his wife in 2012.

A Queensland jury convicted Baden-Clay of murder in 2014, but the state’s Court of Appeal last December downgraded it to manslaughter after his lawyers argued it was possible he could have unintentionally killed his wife during an argument.

Allison’s body was found on a creek bank in Brisbane’s west 10 days after she was reported missing on April 20, 2012.

Allison’s friend and spokeswoman for the family, Kerry-Anne Walker, said the “decision comes with both relief and elation”.

“The law has acknowledged what we, who were closest to her, knew from that very morning Allison went missing – that is – that she was murdered,” she said outside the court.

“Gerard Baden-Clay murdered his amazing wife, Allison.”

She said the evidence in the original trial had displayed Gerard’s intent as well as his character.

“Today’s decision brings an end to Gerard’s attempts to smear Allison’s name,” she said.

“If some were in doubt as to his true nature, his behaviour after Allison disappeared and during the trial must have removed that doubt.”

Ms Walker said Allison loved being a wife and a mother, and had worked incredibly hard to do both to the best of her ability.

“Her legacy will be her beautiful three girls who, surrounded now by their memories of Allison and the love and support of Allison’s devoted family, are thriving in their busy lives,” she said.

“All who know them are confident they will go on to achieve great things.

“I am in awe every day of how well Allison’s parents Geoff and Priscilla and her sister Vanessa deal with their day-to-day busy lives.

“The girls are certainly a tribute to them.”

Allison Baden-Clay was reported missing from her Brookfield home in April 2012 and found dead 10 days later. Photo: Facebook

Judgment cites ‘unintentional’ killing hypothesis

In its judgment, the High Court said the Court of Appeal had “erred in concluding that the jury’s verdict of guilty of murder was unreasonable on the basis that the prosecution had failed to exclude the hypothesis that Gerard Baden-Clay unintentionally killed his wife”.

“By grant of special leave, the Crown appealed to the High Court,” the judgment said.

“It was common ground on the appeal that the respondent killed his wife.

“The High Court held that the hypothesis on which the Court of Appeal acted was not available on the evidence.

“In particular, the Court [of Appeal] accepted the respondent’s submission, made for the first time on appeal, that the prosecution had not excluded the hypothesis that there was a physical confrontation between the appellant and his wife in which he delivered a blow which killed her [for example, by the effects of a fall hitting her head against a hard surface] without intending to cause grievous bodily harm.”

Queensland Law Society president Bill Potts said Gerard Baden-Clay had no further grounds for appeal and would serve a minimum of 15 years in prison.

Mr Potts said the ruling had set an important precedent.

“The way in which circumstantial evidence may be used and post-offence behaviour may be used has now been clarified by the High Court and that in turn can be utilised across a range of cases that are waiting in the wings,” he said.

Gerard Baden-Clay’s defence lawyer Peter Shields said the High Court’s decision would be accepted.

“I am disappointed the High Court did not decide in our favour,” he said.

“Smarter people than I will write very interesting articles about this decision because it really does fundamentally alter the position of the criminal law throughout the Commonwealth.

“The position that has changed significantly is to do with an accused giving evidence, and particular knowledge that an accused may be thought to have.”

Police set up a mannequin at Brookfield, wearing clothing similar to what Allison Baden-Clay was last seen in. Photo: ABC

Ms Walker also praised the authorities who helped with the case.

“I would like to thank and acknowledge again the Department of Public Prosecutions, the Queensland Police Service and all those that helped with the case,” she said.

“Your tireless work and passion for the truth will never be forgotten and you should be also very pleased with today’s decision.”

Premier Annastacia Palaszczuk, who did ballet classes with Allison when she was young, said the family’s fight for justice was now over.

“The sad reality is that no court judgement or jail term will bring Allison back,” she said.

“As life goes on, and it will, there will forever remain a void of the lives of those who were privileged to know Allison.”