HALIFAX -- A Nova Scotia judge who acquitted a taxi driver accused of sexually assaulting an intoxicated passenger failed to recognize the nature of the evidence before him and made several errors in law, a Crown attorney told the province's highest court Wednesday.

Crown lawyer Jennifer MacLellan told the Nova Scotia Court of Appeal that provincial court Judge Gregory Lenehan said three times in his oral decision there was no evidence of a lack of consent or a lack of capacity to consent to the sexual act that took place in Bassam Al-Rawi's cab on May 22, 2015.

However, MacLellan told the three-justice panel there was, in fact, ample circumstantial evidence to prove the complainant, who had no memory of what happened, was incapable of consenting.

"This is not a rejection of evidence ... This is a failure of the trial judge to recognize the evidence before him," MacLellan said.

Lenehan's decision never dealt with the possibility the woman may have been incapable of consenting to sex prior to passing out, she said.

During Al-Rawi's trial, an expert testified that the young woman was extremely intoxicated after drinking five draught beers, two tequila shots and one vodka-cranberry drink while at a downtown bar, MacLellan said.

The forensic analyst determined the woman's blood-alcohol level was as high as 241 milligrams per 100 millilitres of blood -- 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, the attorney said.

MacLellan cited one response to a friend who asked if the woman was OK: "No. I am not got," was the texted reply.

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.

Court heard that when a police 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.

The vehicle was found in a neighbourhood far from the woman's home, only 11 minutes after she got in the taxi shortly after 1 a.m.

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 and his zipper was down.

"This circumstantial evidence created a tight web around Mr. Al-Rawi from which he could not escape," MacLellan told the court.

By suggesting there was no evidence dealing with the woman's capacity to consent, the judge made an error in law, MacLellan said.

Al-Rawi's lawyer, Luke Craggs, said the evidence wasn't as clear as the Crown had suggested.

He said many of the woman's text messages that night had proper spelling and grammar, and he pointed to evidence the woman had an upsetting argument with a friend before getting in the taxi.

"(The judge) decided the evidence correctly," Craggs told the court, adding that the oral decision appeared to be a "reluctant acquittal."

"What happened in the taxi is really unknown ... (The judge) struggled with a gap in the evidentiary record."

Craggs also noted that during the trial the Crown never specifically asked the woman if she did not consent to sex with Al-Rawi.

MacLellan said asking such a question would have been improper, as it could have opened the door to questions about the woman's previous sexual behaviour, which is not permitted in sexual assault cases.

The Crown lawyer said the judge also erred by speculating about the possibility that the woman may have flirted with Al-Rawi or initiated the sexual activity rather than drawing inferences from the facts proven in the evidence.

Lenehan's decision in March, which the Crown is seeking to overturn, concluded the Crown had failed to prove beyond a reasonable doubt that the woman did not consent to sexual activity with the driver.

In his decision, Lenehan said a person is incapable of consent if they are unconscious or are so intoxicated that they are unable to understand or perceive their situation.

"This does not mean, however, that an intoxicated person cannot give consent to sexual activity," he said at the time. "Clearly, a drunk can consent."

Lenehan's words set off a storm of social media criticism and two public protests. Based on a complaint, the decision is the subject of an investigation by a three-member review committee appointed by Nova Scotia's chief justice.

Lenehan's "poor choice of words" suggested the judge was confused about the nature of drunkenness and consent, MacLellan said Wednesday.

The appeal panel reserved its decision.