Only 10 months after being struck off, they can apply to be restored. They can then apply annually to be restored and the GMC must hear their cases.

Thirteen doctors were banned from practicising medicine last year, but eight who had previously been struck off were allowed to operate again.

Two of these were GPs accused of inadequate or inappropriate treatment - the main charge faced by the three Bristol doctors.

Thirteen banned

The General Medical Council - doctors' regulatory body - heard 71 cases in 1997, 59 of which were for serious professional misconduct. Ten charges were dismissed and 13 were banned from operating.

However, banning - the most serious punishment available - may not be permanent. After 10 months, doctors can apply to be restored to the medical register which means they can effectively practice again.

In 1997, eight were restored. These include doctors accused of 'irresponsible prescribing', falsifying medical records, acting inappropriately, indecent behaviour and inappropriate charging. Nine doctors were not allowed back onto the register.

"The majority do not get restored," said a spokeswoman for the GMC, confirming that a decision to ban a doctor means they are effectively barred from operating anywhere in the UK.

Self-regulation

A total of 102 people sit on the General Medical Council. Fifty-four are elected by doctors; 13 are nominated by the Privy Council and 35 appointed by educational bodies.

Doctors can be struck off the medical register for a variety of charges, but the main and most serious accusation is of serious professional misconduct.

However, since last July, the GMC has added a new category of case which covers doctors who show a pattern of poor performance over a long period.

Had this been in place earlier, it could have been used against the Bristol doctors when the hospital's high mortality rates in child heart operations first began to be noted.