Britain risks losing its "moral authority" by not speaking out about the treatment of a U.S. army private accused of providing thousands of sensitive documents to the WikiLeaks website, an MP says.

Welsh MP Ann Clwyd spurred a debate in the British Parliament on Monday night about Bradley Manning, 23, a former intelligence analyst who is being held in a military detention centre in Quantico, Va. He was arrested in May 2010.

Staff at the British Embassy in Washington will be instructed to question the U.S. State Department about why Manning is being kept in solitary confinement for 23 hours a day and is stripped naked each night and given a suicide-proof smock to wear to bed, Foreign Office Minister Henry Bellingham said.

He is checked by guards every five minutes and must respond when they check on him. He is not allowed to sleep between 5 a.m. (7 a.m. on weekends) and 8 p.m., and if he tries to, he must stand or sit up, says his lawyer, David Coombs. He is required to be visible at all times, including at night, which means he has no access to sheets, no pillow except the one built into his mattress, and is only allowed one blanket and one book or magazine in his cell.

He has no contact with other prisoners, even during the hour each day he is allowed out of his cell.

Coombs has complained that his client's treatment is degrading and punitive, a charge the U.S. military has denied.

Coombs claims the way Manning is being treated "serves no purpose other than to humiliate and degrade … I consider it cruel and unnecessary."

Manning faces a host of charges over allegations he supplied classified data to the WikiLeaks whistleblower site.

This is the second time Clwyd, a Labour MP who is the head of an all-party parliamentary committee on human rights, has raised the issue of Manning's treatment in the British Parliament.

Manning's mother lives in Pembrokeshire, Wales, and her son lived there between the ages of 13 and 17.

"I do not want us to get drawn into a discussion of the rights and wrongs of the WikiLeaks revelations," Clwyd said during the debate in parliament, the Guardian newspaper reported. "I would like us now to concentrate on the current conditions of detention for Bradley Manning.

"Manning's case is important because of the message it sends out to the rest of the world about what kind of treatment the United States thinks is acceptable for people in detention."

Human Rights Watch and Amnesty International have also raised concerns about Manning's treatment.

With files from The Associated Press