HALIFAX -- A Halifax taxi driver acquitted of sexually assaulting a drunk and unconscious woman has been ordered to again stand trial in a case that sparked a national debate over intoxication and the capacity to consent to sex.

In a unanimous decision released Wednesday, the Nova Scotia Court of Appeal concluded the original trial judge erred in law by finding there was no evidence of lack of consent.

A three-justice panel found provincial court Judge Gregory Lenehan ignored or disregarded circumstantial evidence showing the complainant did not agree to sexual activity, or that she lacked the capacity to do so.

"Here, the trial judge discounted the substantial body of circumstantial evidence of lack of consent or capacity to consent as 'absolutely no evidence,"' the 30-page decision says.

"On this ground alone, the Crown is entitled to a new trial ... In addition, the trial judge made findings for which there was no evidence. In doing so, he erred in law."

Under the Criminal Code, the Crown was obligated to prove beyond a reasonable doubt the complainant was not capable of understanding the nature of what was happening to her.

During Bassam Al-Rawi's trial, the court heard that a police officer found the young woman in the back of Al-Rawi's cab early on May 22, 2015. The woman, whose identity is protected from publication, told police she couldn't remember what happened after she hailed a taxi.

An expert testified that the woman had consumed five draught beers, two tequila shots and one vodka-cranberry drink while at a downtown bar. The forensic analyst determined the woman's blood-alcohol level was three times the legal limit.

Text messages sent by the woman after she left the bar were riddled with mistakes and were, at times, largely incoherent, court heard. In response to a friend who asked if she was OK, the woman texted: "No. I am not got."

When an officer spotted the woman in the cab at 1:20 a.m., she was lying unconscious, naked from the waist down with her tank top pushed up and her legs propped up on the two front seats, court heard.

The vehicle was found in a neighbourhood far from the woman's home, only 11 minutes after she got in the taxi.

A constable testified that the driver was seen shoving the woman's pants and underwear between the front seats. As well, his pants were undone around his waist, his zipper was down and his body was turned to a position between the woman's legs.

A swab sample later taken from around Al-Rawi's mouth matched the complainant's genetic profile.

At the conclusion of Al-Rawi's trial, Lenehan said he accepted evidence that the woman had urinated in her pants before the cab driver removed them from her while she was in the back seat.

In his oral ruling, delivered last March, Lenehan repeatedly said there was no evidence of a lack of consent or a lack of capacity to consent.

Lenehan's decision sparked public outrage and complaints. Last fall, the province's chief justice asked an independent panel to review the judge's conduct.

The judge also faced sharp criticism for saying: "Clearly, a drunk can consent."

The appeal court found Lenehan's statement was correct in law, but the three justices concluded his application of the consent test revealed a legal error when he equated incapacity only with unconsciousness.

"The trial judge said that the Crown had not proven incapacity beyond a reasonable doubt because, in essence, it was unknown the 'moment the complainant lost consciousness,"' the appeal court's decision says.

"In other words, any mental state short of being unconscious gave the complainant an operating mind with the capacity to consent. With respect, this reveals legal error."

During an appeal court hearing in November, Crown lawyer Jennifer MacLellan said Lenehan's decision never dealt with the possibility the woman may have been incapable of consenting to sex prior to passing out.

Wednesday's ruling included a concurring opinion from Justice Jamie Saunders, who said the trial judge was "simply stating the law" when he observed that a drunk can consent - even if the words he chose were harsh.

"One hopes that the outcry which greeted the release of the judge's decision in this case will not cause him or his judicial colleagues to be cowed in the way they decide the matters that come before them, and that they will continue to judge with the courage, independence and impartiality, their oath and our law demand," Saunders said.