Iraqi hotel receptionist Baha Mousa
Panorama reveals that British soldiers suspected of torturing Iraqi civilian detainees were not brought to justice.
Lawyers who worked on a six-month court martial, which is reported to have cost £20 million, say they fear it failed to get to the truth.
An army whistleblower describes the investigation as "appalling".
Only one of seven soldiers who were charged has been convicted of inhumane treatment.
An Iraqi victim tells Panorama that a key suspect did not appear at the Bulford Camp court in Wiltshire.
The Panorama special called A Good Kicking investigates the torture of seven Iraqi civilians in 2003 while held in British custody in Basra.
One man, a hotel receptionist called Baha Mousa, died and had 93 injuries on his body.
A soldier, who asked to have his identity protected, told Panorama: "What I saw in that cell wasn't interrogation. It wasn't detention. It was torture as far as I am concerned. It was brutal. It was barbaric."
Lieutenant Craig Rodgers and several of his unit from the Queen's Lancashire Regiment were mentioned repeatedly by prosecutors and witnesses in court as being alledgedly involved in the beatings.
But neither he nor any of his men appeared in the dock during the court martial.
Rodgers has since been promoted to captain and is in Germany training British troops for Iraq and Afghanistan.
Two soldiers were cleared on Tuesday of failing to prevent the abuse of the Iraqis. Major Michael Peebles and Warrant Officer Mark Davies denied charges of negligently performing their duties.
Four of their colleagues, including the former commander of the regiment Col Jorge Mendonca, had their cases thrown out.
Cpl Donald Payne was the jailer in charge of the detainees who pleaded guilty to a charge of inhumane treatment.
He is the only soldier to be held responsible for mistreating detainees and is awaiting sentence.
One of the arrested men, Kifah Mousa, was interviewed by Panorama a few months after his release. He's since died in a building collapse.
He said: "They started torturing us before they posed any questions. Basically they were kick boxing us and looked to be really enjoying it."
Former head of the Army, General Sir Mike Jackson told Panorama: "It disturbs me that it is probable that this trial will conclude and we will not know how Baha Mousa died."
"For the vast majority of soldiers they feel uncomfortable, even ashamed perhaps that such deeds are alleged to have been made by members of their army."
A former senior military investigator told the programme of "some very disturbing gaps in evidence."
"There's a whole chain of command involved here, and its patently evident that some key suspects were not appearing in the trial" he said.
Phil Shiner was a lawyer for the victims and told Panorama: "It's soldiers investigating soldiers and then papers are sent up to soldiers who decide who should and shouldn't be prosecuted. It's a cover up. It's a travesty. The military system hasn't got close to establishing what went wrong."
The MOD sent a statement to the BBC after the court martial concluded and said: "Sentencing is not yet complete in this case.
"Today's judgement has been an important one and we will need time to consider fully the serious implications.
"In very difficult and dangerous circumstances in Iraq our forces do a superb job.
However, we need to maintain both operational effectiveness and the public's trust and confidence.
If, as result of this trial lessons need to be learned, we shall do so."
A Good Kicking was broadcast on BBC One on Tuesday 13 March 2007.