Iraqi detainee Baha Mousa was subjected to interrogation tactics branded illegal by the Government's chief law adviser more than 30 years before, an inquiry was told today.
Other senior defence experts told then Prime Minister Edward Heath that conditioning tactics - including hooding, white sound and sleep deprivation - were "morally unjustifiable".
Mr Mousa, 26, died after being beaten by troops in Basra, southern Iraq, in September 2003.
On the second day of investigations into events surrounding the hotel worker's death, Gerard Elias QC, counsel for the inquiry, told how investigations were launched into the use of similar tactics in Northern Ireland.
Quoting minutes taken from a meeting involving the Attorney General in 1972, Mr Elias said: "It was accepted that the in-depth interrogation procedures were and are illegal."
In another report Lord Gardiner said hooding amounted to an assault. The tactics were "unlawful" and "morally unjustifiable", he added at the time.
Mr Elias said the Ministry of Defence believed the techniques would be made illegal.
"Accordingly preliminary consideration was already being given to the possible need for legislation to indemnify those involved in the past and possibly for a way to protect those involved in such activities in the future," he said.
The inquiry has heard how UK troops subjected Iraqis to humiliating abuse, including making them scream in an "orchestrated choir" and forcing one to dance like Michael Jackson.
Mr Mousa's injuries may have been inflicted "with a greater degree of deliberation" than was previously thought, the inquiry heard.
He sustained 93 separate injuries, including fractured ribs and a broken nose, while in the custody of the Preston-based Queen's Lancashire Regiment.
Yesterday a film was released showing Corporal Donald Payne screaming at hooded Iraqi prisoners calling them "apes".
Cpl Payne became the first member of the British Armed Forces to admit a war crime when he pleaded guilty to inhumanely treating civilians at a court martial in September 2006.
He was dismissed from the Army and sentenced to one year in a civilian jail.
Six other soldiers who faced the court martial were all cleared on all counts in March 2007.Reuse content