An investigation is under way today into the case of a wounded Iraq veteran reportedly forced to spend a night in hospital lying in his own faeces.

Jamie Cooper is said to have endured the ordeal because staff at Birmingham's Selly Oak Hospital, where he is being treated, let his colostomy bag overflow.

His ordeal emerged as a charity claimed troubled British veterans of the wars in Iraq and Afghanistan are waiting up to 18 months for NHS mental health treatment.

Services mental health charity Combat Stress described the situation as "scandalous".

Defence Secretary Des Browne pledged to address any problems with delays in injured soldiers getting NHS treatment.

Ministry of Defence figures revealed more than 2100 troops have suffered psychiatric problems after returning from Iraq since 2003.

Combat Stress said more resources were needed to help the thousands of ex-service personnel who will need treatment in future.

The charity, which runs three treatment centres for veterans with post-traumatic stress disorder, warned it was in danger of being overwhelmed.

Serving military personnel, including reservists, normally get rapid treatment through the defence medical services.

But after they leave the forces they must use the NHS, although they are entitled to priority treatment.

On the NHS it normally takes 18 months to get a first appointment to see a psychologist or psychiatrist, Combat Stress said.

Its spokesman added: "It's scandalous that they have to wait so long."

Shadow Defence Secretary Liam Fox said some NHS treatment fell "well below" the levels the armed forces had the right to expect.