The huge scale on which doctors have removed organs for research emerged during the public inquiry into the Bristol heart surgery disaster in March. Consultants disclosed that 11,000 children's hearts were held in centres around the country, many taken without the knowledge of parents.

The huge scale on which doctors have removed organs for research emerged during the public inquiry into the Bristol heart surgery disaster in March. Consultants disclosed that 11,000 children's hearts were held in centres around the country, many taken without the knowledge of parents.

Consent is necessary for a post-mortem examination, unless it is conducted at the request of a coroner. Relatives are asked to sign a form stating that "tissues may be retained" for diagnosis, research or teaching purposes and that they "do not object". There is concern that many parents may not understand this means whole organs can be removed and kept.

At the Bristol inquiry, the heart specialist Professor Robert Anderson, who helped to build up the collection of organs at the Royal Brompton hospital and is now responsible for those at Great Ormond Street, said the practice of taking organs was widespread but admitted surgeons were "wrong" to take without permission. He told the inquiry: 'The pathologist would remove the organs at autopsy - for which we had received consent - so we presumed the consent given for the autopsy permitted us then to retain the organ... I think we were wrong to presume that we had that right."

However he defended the practice on the basis that huge advances had been made as a result in the diagnosis and treatment of congenital heart disease. "I am convinced that morally we were correct to do that," he said. "The advances that we have made would not have been possible had we not retained the hearts and had we not built up these collections."

Professor Anderson, thepresident-elect of the British Paediatric Cardiac Association, later said if the trend to return hearts to parents continued it could damage the development of medical expertise. "If every parent said, 'We want the hearts back', we would not be able to train the next generation of paediatric cardiologists."

Ian Cohen, the Liverpool solicitor representing some Alder Hey families, said he believedparents might be able to take legal action over the length of time organs had been stored. "The fact that a consent form has been signed is likely to be proved in civil court not to give a pathologist any right to keep an organ for longer than is reasonable for inquiries relating to a post-mortem."