Vancouver's controversial Insite clinic can stay open, the Supreme Court said Friday in a landmark ruling.

In a unanimous decision, the court ruled that not allowing the clinic to operate under an exemption from drug laws would be a violation of the Charter of Rights and Freedoms.

The court ordered the federal minister of health to grant an immediate exemption to allow Insite to operate.

"Insite saves lives. Its benefits have been proven. There has been no discernible negative impact on the public safety and health objectives of Canada during its eight years of operation," the ruling said, written by Chief Justice Beverley McLachlin.

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If Insite wasn't allowed to operate it would prevent injection drug users from accessing the health services offered at the facility, threatening their health and their lives, the ruling said. Withdrawing the exemption would even undermine the purpose of the federal drug law, which includes public health and safety, the court said.

The Supreme Court said that if the health minister, currently Leona Aglukkaq, receives applications for more exemptions, she must continue to exercise her discretion and aim to strike a balance between charter rights and protecting public health and safety.

Where there is no evidence that a supervised injection site would have a negative impact on public safety, the minister "should generally grant an exemption," the court said.

The Conservative government is opposed to the Insite operation, and when it came to power it dropped harm reduction from the national anti-drug strategy. Aglukkaq said Friday the government's investments are targeted at prevention and treatment.

"Although we are disappointed with the Supreme Court of Canada's decision today, we will comply," Aglukkaq said in question period. "We believe that the system should be focused on preventing people from becoming drug addicts."

Aglukkaq said the government planned on reviewing the decision.

While the ruling is a victory for Insite, the Supreme Court said  it "is not a licence for injection drug users to possess drugs wherever and whenever they wish."

"Nor is it an invitation for anyone who so chooses to open a facility for drug use under the banner of a 'safe injection facility,'" said the court.

'An incredible victory' supporters say

Supporters of Insite immediately celebrated their victory and expressed relief over the decision.

"This has been the most incredible battle," NDP MP Libby Davies said at the court in Ottawa minutes after the decision. She said Prime Minister Stephen Harper's government has been opposed to Insite based on partisan and ideological principles and never recognized its benefits. It saves lives, she said.

"The Conservative government has been relentless in their opposition, so today's decision by the court just feels like an incredible victory. It feels like a great day," she said.  Insite is in her riding and she said she was thinking of her constituents who use the clinic.

Davies was at the court in Ottawa with Dean Wilson, one of her constituents who used the clinic and helped launch the original court case. A former heroin addict who has been clean for two years, he said he supports more clinics like Insite in other cities, but only if it's right for that community. The floodgates shouldn't necessarily open because of the ruling, he said.

"You need the nurses on side, you need the city on side, you need the local police department on side," the 55-year-old said.

Wilson said he wants to offer an olive branch to the federal government so that all sides can work together to support what he called a gold standard in health services.

In Vancouver a large crowd of supporters at the supervised drug injection site on East Hastings Street in the city's troubled Downtown Eastside site burst into cheers after learning of the ruling on Friday morning.

Joe Arvay, the lawyer who fought the federal government and won, was one of the crowd of health officials, social activists and Downtown Eastside residents.

"Obviously great happiness, great relief — we were nervous. It could have gone the other way," said Arvay.

Dr. Julio Montaner of the B.C. Centre for Excellence in HIV/AIDS said the decision sends a strong message that addiction is a medical condition, and the charter rights of Insite's clients trump the federal Conservative government's wish to shut the facility down.

"Mr. Harper, you had an opportunity to do the right thing. You chose not to do it for whatever ideological or moral restraints you are operating under. The time has now come for you to move on, and accept the rulings of the court," said Montaner.

Dr. Patricia Daly, the public health officer for Vancouver Coastal Health, said the decision by the top court should finally put to rest the debate over whether Insite is safe.

"For those who doubt it, I have to say during my 20 years in public health I have never seen more evidence supporting a public health practice as we have had published around Insite," said Daly.

"I don't think that there is any doubt in the medical community and in the public health community that this service works and it is evidence-based," said Daly.

Dr. Evan Wood with the BC Centre for Excellence in HIV/AIDS, was also on hand to celebrate the decision.

"I think on a personal level there's a degree of happiness with the decision, to say the least, just because we've seen improvements in the health of so many of our patients. And we're aware of the research that programs like Insite save tax dollars," said Wood.

"In terms of the public disorder and public injecting, those issues obviously would have gotten a lot worse if it had to close," he said.

Other regions could open sites

Montaner noted the federal government didn't lose everything in this case when the high court ruled in favour of Ottawa on a jurisdictional issue, saying it has jurisdiction over health-care delivery at Insite.

But he did not anticipate that would prevent any other province or regional health authority from setting up its own supervised injection facility.

Bernie Pauly with the School of Nursing at UVic said the question of jurisdiction will still need some parsing by lawyers. But she said this decision is a boost for those who would like to see a similar facility in Victoria.

"Absolutely, the obstacles are removed, and we have our city, our health authority, are all in support of harm reduction, and so it means we have to move forward. There is no reason not to," said Pauly.

B.C.'s Health Minister Michael de Jong called the ruling "a wise and humane ruling by a unanimous bench."

"Today's ruling will allow the doctors, nurses and staff at Insite to continue to deliver care in a safe environment with a stable future," said de Jong.

Vancouver Mayor Gregor Robertson issued a statement applauding the decision.

"I am very pleased to see today’s ruling from the Supreme Court of Canada in favour of Insite," said Robertson.

"Addiction is a health issue, not a criminal issue. Research, and now the law, confirms our position that safe injection sites such as InSite perform an important health-care role in the lives of people living with chronic addiction-related problems," said Robertson.

Health groups, including the Canadian Medical Association and the Canadian Public Health Association, also applauded the decision.

Long legal battle

Insite, supported by the City of Vancouver and the B.C. government, provides sanitary conditions for addicts while they inject drugs, medical supervision to help monitor for overdoses, clean needles and counselling for those seeking rehabilitation.

The clinic does not supply any drugs.

Insite has supervised more than one million injections, according to the Vancouver Coastal Health Authority, and there has never been a death at the facility. The health authority says there have been more than 1,400 overdoses and that medical staff were able to intervene successfully in all cases.

A study published in the British medical journal The Lancet found that overdose deaths had declined by 35 per cent in the area of Insite, on Vancouver’s Downtown Eastside, since the clinic had opened, compared to a nine per cent drop in overdoses city-wide.

The B.C. Centre for Excellence in HIV/AIDS has said that since Insite opened, there's been a 30 per cent increase in the number of addicts who enter detox.

Other Canadian cities, such as Victoria and Toronto, have said they want to open their own safe-injection clinics, modelled on Insite.

Insite was granted a three-year exemption from the possession and trafficking provisions of the Controlled Drugs and Substances Act when it first opened its doors in 2003.

It was granted two extensions but the Conservative government made it clear in 2008 that it did not support another exemption, and court proceedings were launched to try to save the clinic. Lawyers for the federal ministry argued that the government should not be in the business of facilitating illegal drug use.

The federal health minister at the time was Tony Clement, now Treasury Board president, and the Supreme Court agreed with lower court decisions that found his decision to withdraw the exemption violates Section seven of the charter because it contravenes the principle of fundamental justice.

With files from the CBC's Rik Jespersen and The Canadian Press