The Supreme Court of Canada ruled Friday that journalists do not have a blanket right to shield confidential sources.

The court ruled 8-1 against the National Post and former reporter Andrew McIntosh, who sought to quash a search warrant issued almost a decade ago in a case dealing with a possibly forged document from a secret source linked to a political scandal.

In finding there is no broad protection for journalists to shield sources, the justices said claims of immunity can be argued on a case-by-case basis.

"The law should and does accept that in some situations the public interest in protecting the secret source from disclosure outweighs other competing public interests — including criminal investigations," Justice Ian Binnie wrote on the court's behalf.

"In those circumstances, the courts will recognize an immunity against disclosure of sources to whom confidentiality has been promised."

But Binnie wrote that in this situation, the needs of a police investigation trumped the right to keep sources confidential.