Ontario's Liberal government passed a secret law governing police powers during last year's G20 summit in Toronto that could have led to even more abuses than were witnessed, concludes former chief justice Roy McMurtry in a report released Thursday.

More than 1,100 people were arrested by the 20,000 police who patrolled Toronto during the G20 weekend.

The public, and police, were both mistakenly under the belief that police had the authority to stop, search and detain anyone near the G20 zone, and such searches took place across the city, well away from the summit site.

McMurtry was critical of the government for updating a Second World War law designed to protect public buildings like court houses to give police additional powers during last June's summit, and then failing to tell the public.

"The Public Works Protection Act raises issues regarding the liberty and security of the person in providing for warrantless searches and stopping for identification," writes McMurtry in the report. "(The) potential for abuse is beyond troubling, to say the least."

McMurtry called the law "vague," and warned a vague law can lead to "inconsistent and arbitrary" enforcement.

"Individuals are not provided with sufficient guidance as to what behaviour a law prohibits," he said. "And those in charge of enforcing the law are not provided with clear guidance as to how to enforce it."

The Canadian Civil Liberties Association said McMurtry's report vindicates what it's been saying all along about police abuses during the summit weekend, and again called on Premier Dalton McGuinty to apologize for the secret law.

"There is a need to apologize to the Ontario public who were prevented from knowing that the law had been changed," said association general counsel Nathalie Des Rosiers. "It would be a significant way of showing a recognition that something went wrong and that it ought not to have happened."

The government should finally agree to call a full scale inquiry into the G20, added Des Rosiers, who welcomed McMurtry's report but said it looked at only one aspect of police behaviour during the G20.

"It doesn’t speak to the communications strategy of the police, the way in which the forces were deployed throughout the city, the decision to disperse peaceful protesters, to kettle them and the infiltrations of the different groups," she said. "The report points to the fact there were some significant failures during the G20 and we should get to the bottom of it so it’s not repeated."

McMurtry found the federal government, the RCMP and provincial police all said extra powers for police were not needed, but Toronto police Chief Bill Blair wanted extra authority for the G20 weekend and the province granted it.

"I agree with the observation of the CCLA that the provisions of the (secret law) led to a lack of clarity as to the scope of the search and seizure powers which created many difficulties and conflicts that probably could have been avoided," writes McMurtry.

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