Scores of Iraqis will come to the High Court on Tuesday seeking an "independent" public inquiry into allegations that British interrogators abused, killed and tortured civilians in Iraq.
Public Interest Lawyers (PIL), acting on behalf of 180 Iraqis, allege there were a number of unlawful killings as well as incidents of torture from March 2003 to December 2008 in British-controlled detention facilities.
Two judges sitting in London will hear accusations that civilians were subjected to a number of techniques to disorientate and debilitate them, including deprivation of sleep, food and water.
Sir John Thomas and Mr Justice Silber will be told there was also hooding, forced nudity, sexual humiliation and repeated and lengthy interrogations.
The three-day application is the second legal challenge in a case in which PIL say there was systemic abuse, as opposed to ill treatment by "a few bad apples".
Defence Secretary Philip Hammond plans to investigate the claims through the Iraq Historic Allegations Team (IHAT), which includes members of the Royal Navy Police (RNP).
However PIL are seeking judicial review on the grounds that the RNP lack sufficient independence, because numerous Royal Navy officers were involved in interrogations with the UK Joint Forward Interrogation Team (JFIT).
PIL says a number of unlawful killings and cases of inhuman and degrading treatment were linked to JFIT's activities as interrogators sought to extract information.
They argue justice requires a fully independent public inquiry.
Ministry of Defence lawyers are opposing the application.
A spokesman recently said: "The IHAT is the most effective way of investigating these unproven allegations rather than a costly public inquiry."