Canada's controversial prison for terrorism suspects will soon be without a single inmate.

Even so, it might be premature to call the Kingston Immigration Holding Centre a white elephant from the war on terror.

Records show that officials, who opened the prison only three years ago, always expected it might have a "dormant period."

They anticipate it still might come in handy - after all, they might have to rejail a prisoner who has been ordered let go.

"If there comes a time when there are no detainees remaining in the KIHC ... this agreement will continue," reads a government memo.

It adds that in the event federal officials "must rearrest and redetain" a freed prisoner, there would be only one place to send him: "The detainees would be detained at the KIHC."

The memos, now posted on The Globe and Mail's website, were retrieved under access-to-information laws by York University PhD candidate Mike Larsen.

The records show that Corrections Canada and the Canada Border Services Agency have already come up with a plan to "govern the operation and the staffing of KIHC during any such dormant period."

The six-bunk prison with a small kitchen and visiting room was build on the grounds of the Millhaven penitentiary in the spring of 2006, at a cost about $3-million.

It still costs a couple of million every year to run.

Officials said they needed the facility to warehouse a special category of prisoners, the select few immigrants deemed to "pose a serious security threat to Canadians."

Critics quickly likened the jail to a "Gitmo North," and found it risible on several levels - including the guards' insistence on post-visit strip searches, and their adherence to daily roll calls for the ever-dwindling prison population.

After all, the population did max out at four: Syrian-born Hassan Almrei, Algerian Mohamed Harkat, and two Egyptians, Mohammad Zeki Mahjoub and Mahmoud Jaballah, were sent to the prison when it first opened.

All had already been jailed for years in solitary in conventional jails by that time.

Almost as soon as KIHC opened, the prisoners staged hunger strikes protesting against conditions.

MPs started visiting to assure themselves it was humane. Then, judges made decisions that rendered the jail somewhat superfluous.

The four inmates were freed one by one into strict forms of house arrest, as the Federal Court ruled strict house arrest was better.

The sole remaining prisoner, Mr. Almrei, was ordered released yesterday after spending nearly two years as the KIHC's only inmate.

He will remain jailed until officials come up with a workable release plan.

It's possible the jail might never again be used. Most of the current security cases are legacy cases - some date back to the late 1990s.

It has been years since Canadian officials arrested anyone new under the law.

Last year, one suspect, Mr. Mahjoub, begged federal officials to send him back to the prison.

At the time, he was finding a life of constant surveillance on the outside was worse than life behind bars.

However, he was refused, and lives now under house arrest in Toronto.