Hundreds of body parts have been pointlessly kept by police for years after suspicious death cases were solved, an audit showed today.
Force chiefs apologised to grieving families as it was revealed that 492 major organs and limbs dating back as far as 1960 had been preserved.
Investigators "may have wrongly assumed that the human tissue seized at the post-mortem examination had been disposed of by the medical profession or by some other means", the Association of Chief Police Officers found.
Deputy Chief Constable Debbie Simpson, who led the audit, said there was "no nationally agreed policy to deal with such items at the conclusion of the investigation".
Some relatives may not have been made aware that detectives had kept the remains but officers are now in the process of "sensitively" dealing with the human tissue, she added.
When asked whether families were aware that tissue had been retained, Ms Simpson said "it may well be a case by case basis".
"The added trauma and upset which may have been caused to the families is difficult and we apologise for having to open up those issues for them," she added.
The report was compiled after forces were asked to audit "items identified during the course of the audit as being no longer required for a criminal justice purpose".
The data was described as "just a snapshot" as a cut off date of March 31 this year was established.
Brains and hearts were included in the audit, which did not keep a record of how many people the body parts belonged to.
Police in Northern Ireland recorded the highest volume of "unnecessarily" stored items, with 71.
The report was published days after the partner of Tony Butler, who was murdered by Ulster loyalists 20 years ago, announced she is to take legal action against officers for retaining part of his skull.
The Metropolitan Police kept 39 major body parts, Merseyside stored 37, Cambridgeshire found 35 and West Yorkshire recorded 31.
A total of 13 forces said they did not hold any body parts.
Ms Simpson said "it is clear that this is an area where the police service needs to work with criminal justice partners including coroners, pathologists and defence experts to ensure that we adopt and follow good practice".
She added: "Protecting the interests of families affected has been central to this audit process.
"I will continue to work with our partners on behalf of the police service to ensure that we address the recommendations within this report."
Dr Roy Palmer, of the Coroners Society of England and Wales, said the fact some families were not informed reflected a move from "paternalism to openism" over the years.
"The findings of this report illustrate the problems that arise when the purposes and the appropriate authority for retaining human material at forensic autopsy are less than clear," he said.
"Families affected by the findings of this report are likely to have faced renewed upset in learning that material may have been retained without their knowledge but this review is an important step in assessing and understanding the current picture nationally and provides police services, pathologists and coroners with an opportunity to learn how to improve our processes."