Three British soldiers cleared yesterday of killing an Iraqi teenager "should never have been prosecuted", one of their solicitors said.

The men were accused of forcing 15-year-old Ahmed Jabar Karheem, who could not swim, into the Shatt al-Basra canal in Basra at gunpoint in May 2003.

Prosecutors had alleged that Karheem had struggled in "obvious distress" before disappearing under the water and drowning.

But a military panel at a court martial in Colchester, Essex, took less than five hours to clear the men.

During the trial there was criticism that British soldiers had not received any proper training in the transition period between war and peace-keeping.

A high- ranking Army officer admitted a lack of planning had turned the occupation into a shambles.

Lieutenant Colonel Nicholas Mercer, the Army's senior legal officer for the invasion, said: "There was a total failure to plan for the occupation.

There was only enough time to prepare for war, never mind the occupation."

Sergeant Carle Selman, aged 39, then of the Coldstream Guards and now serving with the Scots Guards, Guardsman Joseph McCleary, 24, and Guardsman Martin McGing, 22, of the Irish Guards were all found not guilty.

A fourth man, Lance Corporal James Cooke, 22, of the Irish Guards, was cleared last month after the judge in the case ruled he should be found not guilty of manslaughter on legal grounds.

The three cleared looked shaken by events but hugged their friends and family outside the court room.

Guardsman McGing's solicitor Fadi Daoud said it had been "an ill conceived case".

"The outcome is a complete vindication of a fine young man who has served his country admirably in a difficult environment without any proper training during a transitional period between combat operations and peacekeeping."

Guardsman McCleary, speaking afterwards, said: "Justice has been served and I would like to thank everyone. I'm looking forward to going home and pleased it's all over."

Chris Wright, solicitor for Sergeant Selman, said his client had served in Northern Ireland, Bosnia, Kosovo and Iraq during 18 years of service. "Colour Sergeant Selman is naturally grateful that the anxiety he and his family have suffered is over."

During the five-week court martial, in which the accused did not give evidence, the panel heard how Karheem was one of four suspected Iraqi looters bundled into the water to "teach them a lesson" a week after the end of the Iraq war.

The court heard that looters were "wetted" in rivers and canals in an attempt to make them feel uncomfortable and persuade them to go home.

"Wetting" was regarded as "minimum force" in the circumstances.

Lt Col Mercer spoke of the Army's lack of organisation: "There was no planning by higher headquarters, no planning or direction was received from the headquarters in Qatar or from Permanent Joint Headquarters in Britain. "There were simply insufficient troops to carry the responsibilities of an occupying power in a belligerent occupation. In Basra, with a population of roughly half a million, there were only 64 military policemen.

"In a perfect world, looting would have been curtailed and looters would have been removed to the military police post.

"In reality the British were massively undermanned and that was impossible."

A spokesman for the Ministry of Defence insisted troops had received the necessary training.

"The Armed Forces are fully aware of their obligation under international law. They are given thorough training courses that include specific guidance on handling prisoners of war, detainees and dealing with the local population."