The Supreme Court of Canada says it cannot find any documents related to explosive new allegations that some of its members intervened in the repatriation of the Constitution.

The court scoured its archives after the recent publication of a book that alleges two of its former justices interfered in the political process and engaged in backroom discussions.

That search came up empty, the court says.

"The Supreme Court of Canada conducted a thorough review of its records and it does not have any documents relevant to the alleged communications by former Chief Justice Bora Laskin and former Mr. Justice Willard Estey in relation to the patriation of the Constitution of Canada," Owen Rees, the court's executive legal officer, said in a statement Friday.

"This concludes the court's review."

In his new book La bataille de Londres, historian and journalist Frederic Bastien writes that Bora Laskin, then chief justice of the Supreme Court, provided information to the Canadian and British governments on the discussions between the justices about the legality of repatriation.

He based that account on British government documents he got under the United Kingdom's freedom of information laws. The Canadian government was less forthcoming in the release of its old material, providing Bastien with redacted pages.

Bastien further claims another high court judge, Willard Estey, also secretly advised the British government in 1980 that the Supreme Court would address the issue.

Bastien suggests that both jurists violated the principle of separation of executive and judicial powers. Bastien's information was gathered during eight years of digging through documents, including British Foreign Office archives.

All provinces except Quebec, then led by separatist premier Rene Levesque, endorsed the Constitution in 1982. Two attempts to bring Quebec on board since then have both failed.

Political controversy in Quebec

The claims in Bastien's book touched off a political firestorm in Quebec.

The provincial government sent Ottawa an official request for access to Constitution-related documents from more than 30 years ago.

Quebec's national assembly also unanimously adopted a motion calling on the federal government to provide more details about the events that led to the adoption of the Constitutional Act of 1982.

NDP Leader Tom Mulcair, whose party reached official Opposition status in the last federal election partly on the back of a strong showing in Quebec, said the Supreme Court's investigation and findings are not credible.

"You won't find something you don't ask for. Those documents were given to Mr. Bastien by the Canadian government ... and large elements were taken out. So the first thing that one would have expected the Supreme Court to do is to ask for the full version, read them, and start an investigation," he told The Canadian Press in an interview.

"Instead, what they seem to have said from this cryptic, one-paragraph statement, is: 'We looked in our filing cabinet and we don't have them.' ...

"It's a clear indication that the Supreme Court had no intention all along of ever dealing with this issue seriously. But unfortunately, it is an extremely serious issue."

In a statement, the Government of Quebec said it is "disappointed with the cursory examination of the Supreme Court, which leaves many questions unanswered." The Parti Québécois government is expected to offer further comment on the Constitution controversy on Monday.