An investigation into a doctor who wrongly diagnosed hundreds of children with epilepsy was postponed today for a second time due to illness.

Dr Andrew Holton, a consultant paediatrician at Leicester royal infirmary in the 1990s, was found to have misdiagnosed 618 children, leaving some unable to walk or see properly.

He was due to face a General Medical Council (GMC) investigation today, but the hearing was abandoned when one of the key parties in the inquiry was taken ill.

A GMC spokesman could not confirm who was sick, or what their medical condition was. A new date for the planned four-day hearing will be decided some time later this week.

The hearing to decide what restrictions to place on him in the future, started in June but was postponed at the time also due an ill witness.

Dr Holton was suspended in 2001 after 11 years as a paediatric neurologist at the Leicester hospital.

An independent NHS inquiry team conducted a full review into his clinical practice, and found that parents had first complained about him almost three years before his suspension.

Their report, delivered in 2003, said the doctor did not have the right training in neurology.

It confirmed malpractice after finding he had wrongly diagnosed 618 of the 1,948 cases reviewed.

Dr Holton has since retrained and now works as a specialist registrar at New Cross hospital in Wolverhampton.

Families of the children he misdiagnosed are still seeking compensation through the courts.

Their claims are expected to run into millions of pounds and take years to complete, although a high court judge agreed a new process to speed them up earlier this year.

The court hearing in June was told that Dr Holton turned children into what parents called "zombies" by prescribing them with debilitating cocktails of drugs they did not need.

Among the parents of children misdiagnosed by Dr Holton is Sue Parr, of Enderby, near Leicester.

Her son Peter, 18, was wrongly diagnosed and said to have been turned into a "maniac" by years of treatment with powerful anti-convulsant drugs.

The GMC has received more complaints about the doctor since its hearing began in April.

In June, members of the Leicester Epilepsy Parents Group handed in some 80 letters.

The group's chairman said at the time he hoped they would spark a separate, public investigation.