Hassan Almrei arrived in Canada in 1999 seeking refugee status and was arrested at his Mississauga home a month after the Sept. 11, 2001, attacks. (CBC)

A federal judge has struck down a national security certificate against a Syrian-born man arrested eight years ago on terror suspicions.

The ruling by Federal Court Justice Richard Mosley effectively frees Hassan Almrei.

The government had been trying to deport Almrei on a security certificate — a seldom-used provision of the immigration law for removing suspected terrorists and spies.

Almrei's lawyer, Lorne Waldman, said from Toronto that his client was "very excited" about Justice Mosley's ruling.

"He goes through all the different allegations that the government has made against Mr. Almrei and rejects all of them one by one," Waldman said. "It's quite incredible."

There could be one more step in Almrei's case, Waldman said. If the judge allows the government to appeal the ruling by formally certifying a question of law in the case, then the matter goes to the Federal Court of Appeal.

The government argued the Syrian native's travel, activities and involvement in a false-document ring were consistent with supporters of Osama bin Laden's al-Qaeda network.

The ruling says there were reasonable grounds to believe Almrei was a security danger when detained in October 2001, but there are no longer reasonable grounds to believe that today.

It also says federal cabinet ministers breached their duties of "good faith and candour" to the court by not thoroughly reviewing the information on file prior to reissuing the certificate against Almrei in February of last year.

Citizenship and Immigration Minister Jason Kenney told CBC Monday that he couldn't comment on the Almrei case specifically because he hadn't read the ruling, but said federal ministers review documents related to security certificates very thoroughly.

"All I can tell you is the ministers take this responsibility very seriously, and obviously we are reviewing what legal mechanism we need to replace or improve the process," Kenney said. "The bottom line is we need to keep Canadians safe."

Sweeping review

The case is another in a series of blows to the security certificate law, which is used to arrest and deport non-Canadians who are considered a threat to national security.

The federal government has launched a sweeping review after acknowledging the system needs fixing.

Certificates have existed for three decades, and more than two dozen have been issued since 1991, when they became part of federal immigration law.

But recent cases have slowed to a crawl — or collapsed altogether — amid legal challenges and upbraidings from judges over miscues by Canada's spy agency.

The government has initiated just six certificate cases — four terror suspects, a hatemonger and an alleged Russian spy — since the Sept. 11, 2001, attacks on the United States.

Among critics, the deportation tool has come to symbolize the worst excesses of the fight against Islamic extremism. Opponents say the process is fundamentally unfair because detainees are not given full details of the allegations against them.

Supporting evidence withdrawn

A case involving Montrealer Adil Charkaoui, a native of Morocco, fell apart recently when the government withdrew supporting evidence, saying its disclosure would reveal sensitive intelligence sources and methods of the Canadian Security Intelligence Service.

Charkaoui, a French teacher and father of three, wants compensation for his six-year ordeal.

Four active cases range from seven to 10 years old, illustrating the legal limbo that certificates can create for detainees.

Mahmoud Jaballah and Mohamed Zeki Mahjoub, both Egyptian, were arrested in 1999 and 2000 respectively, while Almrei was detained in October 2001 and Mohamed Harkat of Algeria seven years ago this month.

All four men were granted release from prison under strict conditions that have controlled virtually their every move while the cases play out in the Federal Court of Canada.