Consultant urologist John Roberts, 60, and Dr Mahesh Goel, 40, walked free after the case against them collapsed.

War veteran Graham Reeves, 70, died five weeks after his healthy kidney was wrongly removed in the operating theatre at Prince Philip Hospital in Llanelli.

Procedures at the hospital were tightened

The prosecution claimed Mr Reeves died from "thoughtlessness, want of due care and negligence."

But Home Office pathologist Dr Andrew Davison - the prosecution's leading witness on the cause of death - told the jury he "could not be sure" Mr Reeves died as a result of the operation.

Judge Mr Justice McKinnon directed the jury to deliver not guilty verdicts.

He said: "Dr Davison cannot be sure the operation played a more than minimal part in Mr Reeves' death therefore the prosecution has to come to an end now."

The Trust hopes that its staff will now be allowed to put this tragic case behind them and to get on with the job of looking after the health of the people of Carmarthenshire

Carmarthenshire NHS Trust

Mr Roberts' wife wept as the judge dismissed the case.

Mr Roberts, of Ty Coch, Swansea, and Mr Goel, whose address was given as Burnley General Hospital, Lancashire, were both awarded costs.

Earlier in the day Dr Davison had told the court it was "probable" the botched operation played a "more than minimal" part in causing the death.

Retired power station worker Mr Reeves underwent the operation to remove his failing right kidney.

But instead his left kidney - his only healthy one - was removed by mistake.

He then went through more procedures in a bid to improve his condition.

Dr Davison said: "He had two further operations that would not have been necessary had the correct kidney been taken out initially.

Mr Roberts had always denied the charge

"He had a prolonged course in hospital after the operation."

Ian Barker, Medical Defence Union solicitor for Mr Roberts, said after the case: "Mr Roberts has asked me to extend his deepest sympathies to Mr Reeves' family.

"He is profoundly sorry about the death of Mr Reeves. Any further comment about the trial would be inappropriate.

"It is impossible to turn back the clock but perhaps something positive may come from this tragedy if the publicity attached to it allows others throughout the country to learn lessons so that simlilar tragedies can be avoided in future."

A spokesman for Carmarthenshire NHS Trust said the case had been a tragedy for everyone involved and it again extended its sympathy to Mr Reeves' family.

The trust was keen to stress that the procedures in place at the time of Mr Reeves' operation had been subjected to two independent audits and, each time, were found to be satisfactory and effective.

Mr Goel also denied manslaughter

Those procedures had been subject to regular reviews and improvement and were further strengthened from the lessons learned, the spokesman added.

"In the two years since Mr. Reeves' death, staff at Prince Philip Hospital Llanelli have worked hard to rebuild the confidence of the patients," he went on.

"The Trust hopes that its staff will now be allowed to put this tragic case behind them and to get on with the job of looking after the health of the people of Carmarthenshire."

Graham Reeves' long-term companion, Lorraine Ashford, said she was shocked by the sudden end to the trial.

"Ordeal"

The 70-year-old widow said: "I am just speechless.

"Graham and I were close friends and the last couple of years have been an ordeal."

Mrs Ashford, a neighbour of Mr Reeves' in Burry Port said she had not been able to bring herself to attend the court trial.

She described bachelor Mr Reeves as a "very private man" who had few surviving relatives.

And she added : "The case has been a very difficult time and has brought a lot of painful memories back."

The widowed mother-of-four knew Mr Reeve most of her life, but only became a close friend after the death of her husband Hector.

Graham and Hector were lifelong friends and served in the Welsh Regiment together in Korea, and later worked together at the Carmarthen Bay Power Station.