An Iraqi man died after suffering an "appalling episode of serious gratuitous violence" in a "very serious breach of discipline" by UK soldiers, a year-long inquiry has found.

Its chairman, Sir William Gage, blamed "corporate failure" at the Ministry of Defence for the use of banned interrogation methods in Iraq.

Baha Mousa died with 93 injuries in British army custody in Basra in 2003.

Prime Minister David Cameron said such an incident should never happen again.

"The British Army, as it does, should uphold the highest standards," he said.

"If there is further evidence that comes out of this inquiry that requires action to be taken, it should be taken".