TORONTO - An Ontario street racing law hailed as the country's harshest could be in limbo after a judge ruled a section of the legislation is unconstitutional because it can impose jail time even though the speeder can't defend against the charges.

Judge G.J. Griffin of the Ontario Court of Justice in Napanee, Ont., overturned the conviction of a woman clocked at more than 50 kilometres per hour over the limit because the way stunt driving is classified means once the offence is proven by facts, it cannot be defended.

Jane Raham, 62, was pulled over for speeding on her way back to Oakville, Ont., just west of Toronto, after driving to Kanata, Ont., to see her daughter who had just had twins.

Raham had testified she had sped up to pass a tractor trailer, which she had always been afraid of, when she was clocked going 131 kilometres an hour in an 80-kilometre zone.

"If one were to describe a stunt driver, the appellant would not immediately spring to mind," the judge wrote in his ruling last Friday.

The justice of the peace in her case, he said, "did not turn his mind to the appellant's testimony about why she was driving the way she was driving, and whether her evidence gave rise to a due diligence defence, as he proceeded on the basis that this was an absolute liability offence, although he called it a strict liability offence."

Street racers will still be charged under the stunt racing laws, but it will be now unconstitutional to convict someone on excessive speed alone unless the judge's ruling is successfully appealed.

Attorney General Chris Bentley said the province will appeal the decision and doesn't believe the law goes against the Charter of Rights and Freedoms.

"From time to time you get decisions that are ones that you wish to appeal, and we'll be seeking leave to appeal this one," he said, calling the legislation an important public safety initiative.

"It's important that people understand that in the meantime, the provisions are still in effect and the police can still lay charges," Bentley said.

The stiffer fines and automatic suspensions of driver's licences were ushered in 2007 by former attorney general Michael Bryant, who has since left the government and is facing charges after a highly publicized incident that claimed the life of a bicycle courier.

Under the law, minimum fines for street racers are $2,000, with a maximum of $10,000, and up to six months in jail -- a penalty Ontario said at the time was the highest in Canada for street racing.

The law requires no criminal intent when speeding is 50 kilometres per hour over the speed limit, which places it under the category of "absolutely liability" under law and essentially makes a conviction automatic.

Toronto lawyer James Morton said he was surprised by the decision and believes it will come as a blow to cases currently before the courts.

"There's really two options: it may be that the prosecution's going to say the decision is being appealed and they'd like to have the charge adjourned until after the appeal is dealt with," Morton said.

"That can increase delay and the charges may get thrown out because of delay. It's certainly going to lead to a lot of these cases being thrown out completely."

Like Bentley, Ontario Provincial Police Sgt. Dave Woodford warned drivers not to take any liberties because of the ruling, noting police can still seize vehicles and licences.

In his ruling, Griffin didn't take issue with the vehicle seizures or licence suspensions but rather the jail time involved in a conviction.

"If they want to lose their vehicle and their licence for seven days, then go ahead," said Woodford.

"If they're caught driving and they don't have a licence, the second offence, now they're charged with driving under suspension."