Members of the Bristol Heart Children's Action Group will meet Hugh Ross, chief executive of the United Bristol Healthcare NHS Trust, in private.

They want to know which children had hearts or other tissue removed at post-mortem examinations without the knowledge or consent of their parents.

The group revealed last week that they believe at least 170 hearts were retained following operations carried out over a period of nearly 20 years up to 1995.

The trust has so far declined to give precise numbers but says it is working with parents to establish details.

Two doctors were struck off and another banned from operating on children last year following an investigation into the deaths of children at the BRI by the General Medical Council.

The trust says the post-mortems were conducted with parental consent but admit that consent for retention was "not as informed as modern standards require".

Retention of organs was standard practice in the UK, it says, with most post-mortems undertaken at the request of the coroner.

The organs were held for education, research and audit purposes, it claims.

The parents say they were unaware of the "systematic" removal of organs although they did know of isolated cases.

It was only last week, they say, that they learned of the scale of the issue.

The parents will ask Mr Ross why there has been delay in telling parents whether or not their child's organs were taken.

They argue that if the organs were held for education, research or audit purposes, there should be an index cross-referencing them to the patient's medical records.

This should simplify the process of identifying the children concerned.

The group also believes that none of the post-mortems for the coroner resulted in inquests.

If that was the case, they ask why the material was retained and on whose authority.

Shocking revelations

The GMC hearing aroused high emotions

Mrs Michaela Willis, the Group's chair, said: "These are questions that parents are asking of us and we are seeking answers after the shocking revelations of last week.

"This is a very distressing time for parents and those whose children's organs were retained need to know as soon as possible."

A UBHT spokeswoman said: "We would not like to pre-empt what might be discussed. We regard this as a confidential meeting between ourselves and the parents."

She added that the trust was working with the group, other parents' groups and individuals to provide the information on retention "as quickly as possible".

"We have to ensure that the information we give is accurate."

A public inquiry into the BRI scandal opens with public hearings in Bristol on 16 March.

It will examine children's heart surgery services at the hospital between 1984 and 1995.

The first inquiry witnesses will be parents recounting their experiences - from their child's initial referral to hospital through to surgery and beyond.