U.S. NAVAL BASE GUANTANAMO, CUBA - Lawyers for Osama bin Laden's former driver want to know why Canadian terror suspect Omar Khadr is getting better treatment than their client.

They have asked that Khadr appear as a witness at a March hearing where they'll call for the prosecution of Salim Ahmed Hamdan to be suspended on grounds the harshness of his confinement is pushing him over the edge.

The pair are linked because they are scheduled to be the first among those held at the U.S. Naval Base in Guantanamo Bay, Cuba, to be tried for war crimes before the specially constituted Military Commission.

Toronto-born Khadr, 21, can spend up to 20 hours a day mingling inside or outside with other detainees on his cell block at the base's medium security Camp 4. Yemeni national Hamdan, about 37 according to military records, is kept in solitary confinement almost around the clock in maximum security Camp 5.

Yet Khadr, accused of lobbing a grenade that killed an American soldier, faces more serious charges than Hamdan, who claims he never joined al-Qaida, but worked in bin Laden's motor pool because he needed the $200-a-month salary.

Military spokespeople say detainees are assigned according to their level of obedience, with "compliant" ones allowed the "communal living" of Camp 4.

But Hamdan's assignment is unrelated to his behaviour, according to Charles Swift, one of his civilian attorneys.

"I hesitate to (guess) what Mr. Khadr's testimony may be, but think he's relevant because I believe Mr. Khadr has information as to why he's there, and Mr. Hamdan is not," he said.

The lawyers will argue in March Hamdan's continued isolation is driving him toward mental instability, and making it impossible for him to focus on his own defence.

He appeared so ill at a December 2007 meeting with Andrea Prasow, another of his lawyers, that she made a special request for his solitary confinement to end, says a court filing. She also asked he be granted a phone call with his wife.

"I am aware that Omar Khadr . . . has received at least one telephone call from his family," she writes.

Hamdan was in a car carrying two surface-to-air missiles when Afghan troops arrested him in November 2001. They handed him over to American forces, who transferred him to Guantanamo in May 2002.

His lawyers, whom he faults for not getting him out of the maximum security stream, have been a thorn in the side of the Bush administration.

With them he challenged the administration's bid to prosecute Guantanamo detainees. The Supreme Court's 2006 Hamdan vs. Rumsfeld ruling struck down an earlier version of the military commission.

Congress created the current commission in the same year. The military, meanwhile, reassigned Hamdan to a maximum security facility in December 2006 after he'd been in Camp 4 for two years.

Emily A. Keram, a psychiatrist who spent more than 70 hours with Hamdan for the defence, writes he risks developing "suicidal thoughts and behaviour."

He remains at the centre of controversy as his lawyers push for access to the top-secret Camp 7 to interview Pentagon-designated "high-value detainees" - among them Khalid Shaikh Mohammed, the alleged mastermind behind the Sept. 11, 2001, attacks.

Hamdan's lawyers are also criticizing the government after a prosecutor admitted Thursday the military can't find his confinement records for 2002.

They believe the records will help them determine whether any statements he made under interrogation were coerced. They believe the top terrorist suspects will help them show Hamdan was not one of bin Laden's inner circle.

The chief military prosecutor, Army Col. Lawrence Morris, told reporters he believes the missing files contain "generally innocuous stuff."

"It depends on how you characterize a record . . . there are records that show what a guy eats for a meal," he said. "Every statement . . . that we are in possession of . . . the defence has."

The government cites security concerns for resisting access to the "high value detainees." To reach them, Morris said, the defence must meet a certain "threshold" indicating why they believe a particular suspect can help their case.

"We can't . . . just provide them the opportunity (to) just knock on a cell and go walking through the compound seeking information," he said.

© Canwest News Service 2008