OTTAWA -- British Columbia does not have to give a tobacco company access to detailed provincial health databases to help it mount a defence in a multibillion-dollar damages trial, the Supreme Court of Canada says in a ruling that will have a countrywide ripple effect.

In a unanimous decision Friday, the high court said the province cannot legally allow Philip Morris International to see raw data from the information banks.

The ruling is the latest development in a 17-year-old effort by B.C. to recoup smoking-related health-care expenditures from tobacco companies.

It helps clarify a key legal point of national interest, as all 10 provinces have filed suits seeking a total of more than $120 billion in damages from tobacco firms.

A trial date of Nov. 4, 2019, has been set in New Brunswick, while other provinces are in preparatory stages.

"The most important thing now is for provinces to aggressively bring their cases to trial," said Rob Cunningham, a lawyer for the Canadian Cancer Society. "The sooner that they can get their cases to trial, the sooner they can be resolved."

B.C. had argued that permitting wholesale access to individual-level health files -- even with personal identifiers removed -- could unduly compromise privacy.

Philip Morris took exception and successfully challenged the province's stance in the B.C. Supreme Court. The decision was upheld by the B.C. Court of Appeal, prompting the province to take its case to the Supreme Court of Canada.

In its decision, B.C.'s appeal court said there was no serious threat to personal privacy in allowing access to the anonymized data.

The Supreme Court of Canada disagreed, pointing to privacy safeguards in special B.C. legislation that paved the way for court action against tobacco firms.

The legislation allows for the use of statistical and research-based information to help advance the case and determine the amount of damages on an aggregate basis.

The B.C. databases at issue are compilations of individual health-care records about individuals including details of medical services and prescription drug use.

Instead of providing the data, the province proposed a compromise that would give Philip Morris International and other companies restricted access through an agreement with Statistics Canada.

Philip Morris objected, saying it needed unfettered access to the anonymized, individual-level data to assess its quality as well as the reliability of calculations based on the information.

The Supreme Court of Canada said that disclosure of such information -- even after names are deleted -- is barred by a provision of the B.C. legislation protecting "health care records and documents of particular individual insured persons."

Writing on behalf of the court, Justice Russell Brown noted that the Supreme Court had previously found the B.C. law to be constitutional, adding that Philip Morris's concern about trial fairness is, at best, premature.

The B.C. legislation requires that any document relied upon by an expert witness be produced at trial, meaning some of the information Philip Morris seeks could eventually be disclosed.

In addition, the law allows a court, upon receiving an application, to order disclosure of a "statistically meaningful sample" of any of the records and documents otherwise protected by the legislation.

"No defendant has yet made such an application and thus no court has yet had reason to consider what would constitute a 'statistically meaningful sample' of the protected documents," Brown wrote.

In a statement, the B.C. Ministry of Health welcomed the ruling.

"Holding tobacco companies accountable is a priority for the province and we are doing everything we can to ensure a successful outcome on behalf of British Columbians."

B.C. privacy commissioner Michael McEvoy, whose office intervened in the case, called it a precedent-setting decision "that will provide greater privacy protection for sensitive health information of citizens in this province and hopefully have wider applications for all Canadians."

-- With files from Beth Leighton and Camille Bains in Vancouver