David Southall, 55, faces being struck off the medical register if his actions are found to amount to serious professional misconduct at a further hearing in August. But the General Medical Council could reprimand him or suspend him.

Professor Southall, a leading expert on abuse, also faces seven further complaints dating back many years over his child protection work on Munchausen syndrome by proxy.

Members of the professional conduct committee of the GMC took more than five hours yesterday to decide the consultant had acted "irresponsibly, inappropriately and misleadingly" in stating that Stephen Clark, 42, had deliberately suffocated his infant sons within 13 months of each other.

The GMC said a theory had been presented as scientific fact and Prof Southall had declared his report true when he was not in a position to know that.

Mr Clark was not present at the hearing in Manchester yesterday and Prof Southall left without comment.

He had admitted contacting police after watching a Channel 4 Dispatches programme in which Mr Clark talked about his wife Sally's 1999 conviction for the murders of Christopher, aged 11 weeks, and Harry, eight weeks.

During the documentary Mr Clark spoke of a nosebleed and choking incident suffered by Christopher while he was alone with his father in a London hotel. After watching the programme Prof Southall, consultant paediatrician at North Staffordshire general hospital, said he had felt stunned. Based on his research he believed that healthy babies do not have nosebleeds and near collapses unless they had been deliberately suffocated.

He spoke to police officers, social workers and experts in the case and filed a report stating his "near certainty to certainty" that Mr Clark, not his wife, had killed the babies and that his surviving son was unsafe in his care. He later said this was "beyond reasonable doubt".

Prof Southall had admitted to the GMC that he made the allegations without seeing the medical records in the case or speaking to the Clarks. He admitted refusing the chance to put a caveat into his report outlining the limits of his information. His actions, four years ago, sparked a review of the surviving son's care in which social workers and a guardian considered removing the boy from Mr Clark.

At the hearing yesterday Denis McDevitt, chairing the GMC panel, said Prof Southall's report amounted to an abuse of his professional position.

He also said the consultant paediatrician's initial contact with police immediately after seeing the programme in April 2000 was "precipitate" and that he had acted "irresponsibly" in other areas.

Giving evidence at the hearing last week, Mr Clark, whose wife had her murder convictions quashed on appeal last year, said he thought the professor's allegation was a "sick joke" when he first learned of it in the summer of 2000.

Prof Southall told the hearing he had acted at all times to protect a child he believed was at risk.