John Roberts and Mahesh Goel had denied serious professional misconduct

Consultant urologist John Gethin Roberts and surgeon Mahesh Goel are accused of serious professional misconduct in connection with the operation in January 2000 on Graham Reeves, 69, at Llanelli's Prince Philip Hospital. They both deny the charges.

On Tuesday, the General Medical Council decided that the medics were wrong, that they did have a case to answer, and it is now considering if that error amounted to serious professional misconduct.

Addressing the hearing, Mr Roberts, who was supervising the surgery, said the mistake would hang over him for the rest of his life.

"On this particular day I made an error... I am prepared to accept that," he said.

"It is something regrettable, something I will carry with me as a burden for the rest of my days."

Last week, Mr Roberts told the hearing how he had collected Mr Reeves' x-rays but read them the wrong way round and noted that the patient should a left nephrectomy - a mistake.

Describing the events before the operation, he said: "My problem was that I looked at the notes and had the wrong impression in my head. I'll kill myself for the rest of my days."

His solicitor Alan Jenkins said his client "carries no direct responsibility for what happened in this case".

"Quite clearly what happened is that a junior doctor made an error and set in (motion) a chain of events.

"Checks and counter-checks that would normally be made were not."

Graham Reeves died five weeks after his wrong kidney was removed

He said surgical practice meant it would not have been unusual for a surgeon like Mr Roberts to have left checks to his registrar Dr Mahesh Goel - not present at the hearing and thought to be living in India - who was removing the kidney.

On Tuesday, Leighton Davies QC, for the GMC, told the disciplinary hearing that Mr Reeves was "failed and failed miserably in his trust and expectations" and that there was not one, but two consent forms stating clearly which kidney was to be removed.

The doctors' behaviour, he added, was a breach of fundamental and elemental duty and that was a dire failure on the part of each doctor.

Mr Reeves, a Korean war veteran, was transferred to Morriston Hospital in Swansea but his condition deteriorated. He died five weeks after the botched operation on 1 March 2000.

Both doctors were cleared of manslaughter at Cardiff Crown Court in June 2002.

The prosecution's case collapsed after an expert pathologist told the court he could not be sure Mr Reeves died as a result of the mistake.