The General Medical Council admitted yesterday that it may have been "unduly lenient" in clearing a doctor accused of serious professional misconduct relating to a victim of Harold Shipman.

David Lyle Bee, a pathologist, was severely criticised by the independent inquiry into the GP's multiple murders for failing to spot suspicious factors during his post-mortem examination in 1995 of Renate Overton, a patient of Shipman's. Dr Bee concluded that Mrs Overton died of natural causes although Shipman had killed her with a massive dose of morphine.

Dame Janet Smith, in her report on Shipman, said Dr Bee's conduct had been "manifestly inadequate", and up to 100 lives could have been saved if he had investigated Mrs Overton's death properly. Shipman murdered more than 200 people before he was arrested in 1998.

The GMC accused Dr Bee, 74, of serious professional misconduct and he admitted errors. At a hearing last month, the GMC's professional conduct committee found his actions "fell below the standard of care that might reasonably have been expected" but cleared him because he had good references and had retired.

But yesterday the GMC issued a statement saying: "The GMC take the view that the PCC decision in the case of Dr Bee may be unduly lenient." It has asked the supreme disciplinary body, the Council for Healthcare Regulatory Excellence, to refer the case for a High Court review.

It is the first time the GMC has asked for one of its own judgments to be reviewed in such a way.