The Ministry of Defence has said it is "extremely sorry" for the death of an Iraqi teenager who drowned after being "forced" into a Basra canal by four British soldiers.
Ahmad Jabbar Kareem Ali, 15, drowned in the Shatt Al Basra canal in May 2003 after he was detained by British troops on suspicion of looting near the Basra General Hospital.
A report by former High Court judge Sir George Newman found the teenager was "aggressively manhandled and assaulted" after his arrest before being taken to the waterway in an armoured vehicle.
Once at the canal Ahmad and three other suspected looters were forced into the water to get a "soaking", but the teen got into difficulty and drowned.
The report said the soldiers' failure to help was the "plain and certain" cause of the boy's death.
"His death ensued because he was forced by the soldiers to enter the canal, where, in the presence of the soldiers, he was seen to be in difficulty, and to go under the water.
"Notwithstanding the unlawful treatment involved in getting him into the water, his death could have been avoided because he could and should have been rescued after it became clear that he was floundering."
The soldiers were tried in a British court for manslaughter and acquitted in 2006.
The report described how, following the toppling of Saddam Hussein in April 2003, the southern Iraqi city had descended into a "state of chaos".
The police force was ineffectual and in the absence of a court system looters could not be dealt with.
The report said the soldiers' actions gave rise to "grave concerns" about their ability to cope with their orders and the adequacy of the resources available to them.
It also highlighted serious concerns over the soldiers' training and ability for troops in Basra to "act as both policemen and combatants simultaneously".
An MOD spokesman said: "This was a grave incident for which we are extremely sorry. We are committed to investigating allegations of wrongdoing by UK forces and will use Sir George's findings to learn lessons to help ensure nothing like this happens again."
The Iraq Fatality Investigations (IFI) were set up in 2013, with the first three chaired by Sir George.
The IFIs provide an inquisitorial investigation akin to a coroner's inquest in order to meet investigative requirements under the European Convention on Human Rights.