A mother who lost a baby daughter and whose other little girl was brain damaged has launched an appeal over a decision to take no disciplinary action against paediatricians involved in breathing tank experiments on babies.

The General Medical Council twice rejected complaints from parents Carl and Debbie Henshall over University Hospital of North Staffordshire specialists Professor David Southall and Drs Martin Samuels and Andrew Spencer.

The couple, from Clayton, Staffordshire, claim the tanks were linked to the death of their two-day-old daughter Stacey and to the brain damage of their other girl Sofie.

Philip Havers QC, representing the mother, called on Lord Justice Auld, Lord Justice Sedley and Lord Justice Jonathan Parker to quash the decision not to order a disciplinary hearing.

He is claiming that the GMC acted unfairly in failing to disclose to the mother Prof Southall's response to her complaints.

In a three-day hearing, Mr Havers is arguing that the Preliminary Proceedings Committee, which makes recommendations on whether or not to refer matters to the Professional Conduct Committee, failed to give proper weight to the evidence and failed to apply the correct test for referral. The three specialists had worked on the hospital's trials into the controversial CNEP treatment - negative pressure chambers used in the early 1990s to try to help sick, premature babies breathe without the need for traditional ventilation.

The couple allege the health specialists did not give properly informed consent for their girls to be placed into the CNEP tanks.

The action - funded by legal aid - comes the week after Prof Southall survived a legal move by a health watchdog body to have him struck off over an unrelated matter.

The paediatrician had told police that Cheshire lawyer Steve Clark had murdered his two sons.

The GMC found him guilty of serious professional misconduct and banned him from child protection work for three years.

The hearing continues.