Mr. Justice Simon Noel said today that several CSIS witnesses will have to be recalled to face questioning from Special Advocates, who act on Mr. Harkat's behalf to ensure fairness in a closed-door process that could lead to his removal from Canada.

“Once the Court has evidence that leads it to question the completeness of the information being provided to it by the Ministers – in apparent violation of their obligation of utmost good faith – it must allow the Special Advocates access to all information which they have a need to know,” Judge Noel said.

The judge listed several opportunities that CSIS and federal lawyers had in recent years to provide information about the reliability of the source to the court's attention, yet it failed to do so.

“This Court will be reviewing all orders issued and evidence provided to date in this proceeding to see if any further judicial action is required to preserve the integrity of the administration of justice,” he said.

Today's development threw the Harkat case into immediate disarray, derailed a hearing that was set to commence on Monday to determine whether the Harkat security certificate is reasonable.

The ruling also appeared to bear out criticism that was levelled at anti-terrorism provisions when they came into existence after the 9/11 terrorist attacks in New York and Washington.

“During closed hearings, the Court has reminded counsel for the Ministers of the Ministers' obligation to act in utmost good faith in these proceedings,” Judge Noel said. “In particular, relying on its jurisprudence, the court commented on the duty of the ministers to provide all information which would tend to weaken their case against Mr. Harkat.”

He said it is vital that the courts uphold legal principles and ensure that all parties before them – including the government – do the same.

“Persons in positions of authority within government whose actions impact on the rights and liberties of Canadians must be held to account for even the slightest disregard for this principle,” Judge Noel said.

Judge Noel also said that a hearing will take place on June 2 to determine the legality of a major police search undertaken on Mr. Harkat's home on May 12.

During the raid, officials seized a computer and documents that Mr. Harkat's lawyers said are necessary to prepare his defence in an upcoming hearing.

The Algerian-born Mr. Harkat was held in a Canadian prison from 2002 to 2006 on a security certificate, alleged by the Canadian Security Intelligence Service to be an al-Qaeda sleeper agent with ties to Osama bin Laden. He has never been charged with a crime, but has been under strict bail conditions at his home since his release.

“In our estimation, this goes far, far, far beyond their rights as accorded to them in that document,” Matthew Webber, one of Mr. Harkat's lawyers, said at the time. “And you know, it's just abusive.”