The British Defense Ministry established a panel to investigate claims that British forces mistreated Iraqi civilians. One of the claims involved the death of Baha Housa, 26, who died while in British military custody in 2003.
British forces were accused of using controversial interrogation techniques on some prisoners. An inquiry determined that Mousa endured stress positions and "hooding," controversial practices banned in 1972 following a similar investigation into the treatment of detainees in Northern Ireland.
The England and Wales High Court said there were "about 40" similar cases of abuse. The court said it was satisfied with how the panel conducted the investigation but said there were lingering concerns given the number of cases.
"The task of investigating and inquiring into the very large number of deaths occurring at many different times and in different locations requires a new approach if it is to be achieved in a timely, cost-effective and proportionate manner that discharges the very important investigative duties imposed upon the state," the court said.
Inquiry Chairman William Gage in 2011 said there appeared to be widespread ignorance among British soldiers as to how prisoners of war were to be treated.
British Cpl. Donald Payne was convicted of war crimes in 2007 in relation to Mousa's death and served one year in prison.