HALIFAX -- The Crown says a sexual assault charge against a Halifax taxi driver was dropped because there was no realistic prospect of conviction.

Farset Mohammad's judge-alone trial, in relation to an alleged sexual assault in a cab in downtown Halifax in 2015, was scheduled to begin in Nova Scotia Supreme Court Monday.

But Crown lawyer Kim McOnie told Justice Timothy Gabriel they would not be calling evidence in the case.

The judge then told Mohammad, who was sitting in the public gallery, that the sexual assault charge against him had been dismissed.

"You're free to go, sir," he told him.

Outside of court, McOnie said the Crown determined there was no realistic prospect of conviction.

"I'm not going to talk about the evidence. It was a combination of factors," said McOnie. "The Crown's mandate is not to proceed if there's no realistic prospect of conviction."

A number of Halifax taxi drivers have faced allegations of sexual assault in recent years.

In January, a taxi driver acquitted of sexually assaulting a drunk and unconscious woman was ordered to again stand trial in a case that sparked a national debate over intoxication and the capacity to consent to sex.

The Nova Scotia Court of Appeal had concluded the judge that presided over Bassam Al-Rawi's trial erred in law by finding there was no evidence of lack of consent.

A decision is expected Friday in the case of Seyed Mirsaeid-Ghazi, accused of groping a female passenger in October 2015.

The Crown in that case alleges Mirsaeid-Ghazi rubbed the woman's thigh and slid his hand down the top of her dress and touched her bare breast as she sat in the front seat of his cab.