Judicial review proceedings in the name of Al-Sweady, one of the deceased, were issued in late 2007.
The allegations were that Iraqi nationals were detained after a firefight, known as the Danny Boy Battle, with British soldiers in Iraq in 2004 and unlawfully killed at a British camp, and that others had been mistreated at that camp and later at a detention facility.
The Ministry of Defence found no credible evidence to support these allegations, but failings in the disclosure process meant that the Department could not reassure the court that it was in possession of all the material it needed to make rulings on these matters.
As a result, the Ministry of Defence proposed that there should be a fresh investigation of the allegations, either by the Metropolitan Police Service (MPS) or in the form of a public inquiry. Following a scoping exercise the MPS informed the court that it would not undertake an investigation.
Therefore a public enquiry was announced. Mr Ainsworth said in a Written Ministerial Statement issued to Parliament today:
"A public inquiry into the allegations will be held under the Inquiries Act 2005. It will be chaired by Sir Thayne Forbes, who retired from the High Court Bench last year.
"Sir Thayne's wide experience will be invaluable and I am grateful to him for taking on this important task. He has decided to chair the inquiry alone, that is without other panel members. Whether he appoints assessors who can assist him with expert knowledge and advice is a matter for him."
"Although there have been instances of misconduct, only a tiny number of individuals have been shown to have fallen short of our high standards. Allegations of abuse are however taken very seriously."
Defence Secretary Bob Ainsworth
The inquiry's terms of reference are:
To investigate and report on the allegations made by the claimants in the Al-Sweady judicial review proceedings against British soldiers of (1) unlawful killing at Camp Abu Naji on 14 and 15 May 2004, and (2) the ill-treatment of five Iraqi nationals detained at Camp Abu Naji and subsequently at the divisional temporary detention facility at Shaibah Logistics Base between 14 May and 23 September 2004, taking account of the investigations which have already taken place, and to make recommendations.
Mr Ainsworth added:
"Over 120,000 British troops have served in Iraq and the conduct of the vast majority has been of the highest order.
"Although there have been instances of misconduct, only a tiny number of individuals have been shown to have fallen short of our high standards. Allegations of abuse are however taken very seriously.
"The inquiry will, of course, have the full support of the Ministry of Defence. Arrangements are being made to ensure that personnel who will be required to assist the inquiry are provided with the necessary legal support.
"Much work is in hand to ensure that the difficulties over disclosure which arose in the judicial review proceedings are resolved and that the inquiry has all the material it needs."