The use of drug-sniffing police dogs in the random search of a southwestern Ontario school and a Calgary bus terminal was unconstitutional, the Supreme Court of Canada ruled Friday.

In a 6-3 decision, the top court ruled that the actions breached Section 8 of the Charter of Rights and Freedoms, which covers what constitutes reasonable search and seizure.

The ruling, which could have an impact on police powers across the country, centred on two cases.

The first case involved an unexpected police visit to St. Patrick's High School in Sarnia, Ont., in 2002. During that visit, students were confined to their classrooms as a trained police dog sniffed backpacks in an empty gymnasium.

The dog led police to a pile of backpacks, one of which contained marijuana and magic mushrooms. A youth, identified only as A.M, was subsequently charged with possession of marijuana for the purpose of trafficking.

But police admitted they didn't have a search warrant or any prior tip about drugs in the school. The officers had instead visited on the basis of a long-standing invitation from school officials.

In 2004, the Ontario Court of Appeal upheld a previous trial judge's decision to exclude the drugs as evidence and acquit the youth. The court referred to the incident as "a warrantless, random search with the entire student body held in detention."

'No proper justification'

In Friday's ruling, the Supreme Court wrote that while "a warrantless sniffer-dog search is available where reasonable suspicion is demonstrated," in this case, "the dog‑sniff search was unreasonably undertaken because there was no proper justification."

The court wrote that students' backpacks "objectively command a measure of privacy."

"No doubt ordinary businessmen and businesswomen riding along on public transit or going up and down on elevators in office towers would be outraged at any suggestion that the contents of their briefcases could randomly be inspected by the police without 'reasonable suspicion' of illegality," the court wrote.

The companion case involved Gurmakh Kang Brown, who was found with cocaine and heroin after his bags were flagged by a drug-sniffing dog at a Calgary bus terminal in January 2002.

The top court wrote that the police had no evidence that any crime had been committed and that there was nothing to establish that bus depots in general or in Calgary in particular were rampant with drug dealers.

The court wrote that the fact that buses going from Vancouver to Calgary are sometimes used by drug couriers is not sufficient justification to submit every passenger on every bus to a random sniff search.

Crown lawyers have argued the sniffer dogs don't constitute a search and only provide information that could lead to one.

They have said that smells in public air aren't private and compare it to officers detecting an odour in the air.

Disappointed with decision

Karl Walsh, president of the Ontario Provincial Police Association, said he was disappointed by the decision and that the ruling will serve to decrease public safety.

He said officers who are in schools, train stations and bus terminals are there because of a drug problem.

"If you think we have a drug problem or had a drug problem then, we're going to have a big drug problem now," he told CBC News. "Where there are drugs, there are weapons, so essentially what's happened is the safety of our officers and the safety of the public have been placed in increased jeopardy."

Opponents counter that it's more intrusive and allowing such techniques could lead to widening the powers of police to conduct random searches in public places such as churches, schools and shopping malls.

Lawrence Greenspon, a human rights lawyer, praised the decision, saying it sends a message to students that their charter rights will be upheld.

"I think it sends a very strong message to the next generation that we're not just going to teach you about the Constitution in your classroom but we're going to actually put it into practice in the hallways, in your desks and in your knapsacks."

Greenspon also rejected the idea that sniffer dogs had any effect on drug use.

"I think the notion that sniffer dogs and these random drug searches by police kept drugs limited in high schools is nonsense, absolute nonsense," he said. "There's no evidence to suggest that whatsoever."

With files from the Canadian Press