Britain's army chief said the death of an Iraqi detainee in Basra had cast a "dark shadow" over its reputation, after an inquiry found he had suffered "gratuitous violence" at the hands of soldiers.
Hotel receptionist Baha Mousa, 26, was hooded, beaten and held in stress positions along with nine other Iraqis following their detention by 1st Battalion the Queen's Lancashire Regiment (1QLR) in September 2003, the inquiry found Thursday.
Mousa, a father of two, died 36 hours after he was arrested, having sustained 93 separate injuries, including fractured ribs and a broken nose.
The three-year inquiry, led by retired judge William Gage, said numerous soldiers were involved in the abuse and he accused others of a "lack of moral courage" in failing to report what was happening.
It also said the the Ministry of Defence was guilty of a "corporate failure" to prevent such mistreatment, saying it had no proper doctrine on interrogation methods when Britain joined the US-led invasion of Iraq in March 2003.
General Peter Wall, the head of the army, offered an unreserved apology.
"The shameful circumstances of Baha Mousa's death have cast a dark shadow on that reputation and this must not happen again," he said.
Some soldiers had already been suspended from operational duty and military service, he told Friday's Guardian newspaper.
Prime Minister David Cameron said the inquiry detailed a "truly shocking and appalling incident" and he raised the possibility of further prosecutions in the case, something Mousa's family have called for.
Seven soldiers were charged over the abuse in 2005, but six were cleared in a court martial. Cameron said: "If there is further evidence that comes out of this inquiry that enables further action to be taken, it should be taken."
However, he stressed that the abuse "is not in any way typical of the British army that upholds the highest standards".
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Defence Secretary Liam Fox promised the government would use the inquiry's findings "to see whether more can be done to bring those responsible to justice."
The inquiry found Mousa's death had been caused by a combination of his injuries -- many of them inflicted by one soldier, Donald Payne -- and his weakened physical state caused by his mistreatment, the extreme heat and a lack of food and water.
Payne had a "particularly unpleasant" method of assault which included punching or kicking detainees to make them groan in an orchestrated "choir", Gage said.
The soldier pleaded guilty to inhumanely treating civilians and was jailed for a year in 2007, becoming the first member of the British armed forces to be convicted of a war crime.
A year later, the Ministry of Defence agreed to pay Mousa's family and the other detainees a total of £2.83 million ($4.5 million, 3.2 million euros).
Although Britain banned the use of hooding and painful stress positions in 1972, Gage found a lack of knowledge of this prohibition, which he blamed on "corporate failure" by the Ministry of Defence.
While such practices were "standard operating procedure" among Payne's regiment in Iraq, they were "wholly unacceptable", he added.
Gage concluded that the abuse "constituted an appalling episode of serious gratuitous violence on civilians", adding that "they represent a very serious breach of discipline by a number of members of 1QLR".
Nicola Duckworth, Amnesty International's Europe and central Asia director, called for those responsible to be "held accountable for their actions and brought swiftly to justice, including in criminal proceedings."
The inquiry strongly criticised the regiment's former commanding officer, Colonel Jorge Mendonca, one of those cleared at the court martial.
While accepting Mendonca's claim that he did not know about the abuse, Gage said: "As commanding officer, he ought to have known what was going on in that building long before Baha Mousa died."
About 46,000 British troops were deployed to Iraq at the height of the conflict, with the vast majority withdrawn in 2009.