Photo: The Canadian Press

Prime Minister Pierre Trudeau looks on as Cuban President Fidel Castro gestures during a visit in Havana on Jan. 27, 1976. Canada's spy service destroyed a Cold War dossier on Pierre Trudeau in 1989 instead of turning it over to the national archives, The Canadian Press has learned. 

The Canadian Press has learned that Canada's spy service destroyed a Cold War dossier on Pierre Trudeau in 1989 instead of turning it over to the national archives.

The Canadian Security Intelligence Service says the secret file on the former prime minister was scrapped because it fell short of the legal threshold for retention by either the service or the archives.

News of the decision to purge the file, which is coming to light only three decades later, has stunned and disappointed historians.

John English, who wrote an acclaimed biography of Trudeau, says the move is outrageous, and the explanation offered by CSIS is weak.

Steve Hewitt, who has spent years chronicling the country's security services, calls the destruction a crime against Canadian history.

The Trudeau file was among hundreds of thousands the Mounties inherited in the 1980s after the RCMP Security Service was dissolved following a series of scandals.