The criticism came as Dr John Roylance, former chief executive of the hospital at the centre of the Bristol case, began an appeal against the GMC's ruling last year that he be banned from practising.

The case is being heard by the judicial committee of the Privy Council which includes law lords and senior judges.

Dr Roylance was found guilty of serious professional misconduct in connection with the deaths of 29 young children at Bristol Royal Infirmary in the late 1980s and early 1990s.

He was accused of not taking action over allegations that the hospital's survival rate for heart operations on children was far lower than average.

Bias

Dr Roylance's counsel, QC Robert Francis opened the appeal by criticising Sir Donald Irvine, president of the GMC.

He said Sir Donald had hidden the fact that his grandchild was being treated for a heart condition at the start of the seven-month GMC inquiry.

He said this meant Sir Donald had "clear emotional links" with the parents of the babies who died or were disabled after heart operations.

He stated: "It must be very difficult for the grandfather of a child undergoing heart treatment to divorce himself from the distress and understandable anger being expressed by parents of children involved in these cases, parents who were in continuous attendance in the public gallery and who were demonstrating outside the hearing.

"For this was a case where the committee were under an enormous amount of pressure ...it was very important that there should be no sign at all of partiality."

Mr Francis accused Sir Donald of "descending into the arena," and forgetting his "quasi judicial" role as president of the GMC and chairman of the Professional Conduct Committee which was conducting the inquiry.

Mr Francis also stressed that Dr Roylance was not criticised for his work as a practising doctor, but as a manager.

He said he had nine hospitals to juggle and was not an expert in paediatric heart surgery.