The death of Baha Mousa was one of a number of cases where British forces were accused of the mistreatment of Iraqi prisoners.
The military is taking major steps to try to stamp out such abuses.
A rash of legal actions in the wake of the 2003 invasion of Iraq led many to wonder if the British Army, with its excellent training and much vaunted experience in Northern Ireland, might be guilty of ill-discipline and wide-ranging abuses of civilians on the streets of Basra.
A series of courts martial resulted in few convictions, leaving many unanswered questions.
In the most notorious episode, involving a Basra hotel receptionist, Baha Mousa, no-one was found guilty of his death in detention, even though it was never disputed that he was beaten to death while in the hands of the Queen's Lancashire Regiment in September 2003.
The government is expected to announce that no further criminal lines of inquiry are being pursued in the Baha Mousa case, but at the same time reveal how the Army intends to avoid anything like this happening again.
Critics will accuse the Ministry of Defence of failing to bring Baha Mousa's killers to justice, but the lengthy investigation by Brig Robert Aitken, head of personnel strategy, indicates that the Army is serious about learning lessons.
It doesn't believe its soldiers have been involved in systematic abuses, but it clearly recognises that pre-operational training needs to improve to avoid similar situations in the future.
In particular, soldiers involved in a rapid transition from war fighting to peace-keeping or policing operations need much clearer guidance than they have received in the past.
Northern Ireland may have been a vital proving ground for many soldiers, but they were never asked to be policemen as well.
In the anarchy that quickly spread in the wake of the invasion of Iraq, with indigenous security forces destroyed or disbanded, this is precisely what British soldiers found themselves saddled with.
In the 2005 court martial in Germany of members of the Royal Regiment of Fusiliers, whose abuses came to light through publication of so-called "trophy photos", it was clear that uncertainty over the handling of detainees, as well as ignorance of the Geneva Conventions, were contributing factors.
Nor was it just "squaddies" who were confused. Testimony revealed that officers sometimes lacked the necessary understanding too.
It's taken Brig Aitken three years to complete his work - partly because of the need to wait for the completion of the various relevant courts martial - but the Army has already been making changes.
A glossy training video on the treatment of prisoners, produced in 2005, and set in a convincing Middle Eastern environment, is clearly designed to incorporate lessons learned from some of these dark episodes.
Prisoners are never shown hooded, soldiers are told never to conduct "tactical questioning" unless properly qualified, plastic cuffs are used only on uncooperative prisoners (and even then, not so tightly that a thumb cannot be placed between the cuff and the wrist), and soldiers are told never to take photos of prisoners.
Throughout the simulated operation, which the video says is based on real events, soldiers address the camera, emphasising the need to respect the human rights of prisoners, to follow procedures and make absolutely no exceptions.
Similar videos have been used in training in the past, but rarely with such a high level of realism.