An investigation into the use of sedation on children at a former St Albans psychiatric hospital has found that practises did not meet the standards at the time.

Operation Meadow was a criminal investigation into historical reports of excessive use of sedation on patients at Hill End Adolescent Unit from 1969 until its closure in 1995.

The three-year investigation, which was led by the Bedfordshire, Cambridgeshire and Hertfordshire Major Crime Unit, examined the standard of treatment and the use of sedation on children – including whether sedation was used outside of normal therapeutic treatment.

More than 100 adults who spent time at Hill End as children were interviewed by the inquiry team. A total of 70 former staff were traced and questioned, and remaining medical records were recovered and examined.

The investigation concluded that the use of sedation at Hill End did not meet the standards of the day. Some medical records show cases of children being given adult doses and were repeatedly sedated.

There is, however, insufficient evidence to support any arrest or prosecution.

Alongside the investigation into the misuse of sedatives, officers have looked into allegations of sexual assault at Hill End.

These have all been fully investigated, however, there is insufficient evidence to support any arrest or prosecution.

Det Supt Jerome Kent said: “We know that this has been a long process but we had a fundamental responsibility to all those involved to fully investigate the allegations in relation to Hill End Hospital Adolescent Unit. Non-recent cases are always challenging and those who stayed at the unit have been incredibly courageous in speaking to officers about their experiences.

“Myself and the investigation team would like to thank them for speaking out and we understand that doing so will have brought back many distressing feelings and that this process will have caused many to re-live the trauma of their time at Hill End.

“While the investigation is unable to progress further for the reasons outlined, we hope that those who came forward to share their accounts with us will find some closure in the knowledge that they have been listened to, taken seriously, and a full and proper investigation has taken place.”

Hertfordshire Constabulary takes all reports of sexual and physical abuse seriously, regardless of how long ago the offence may have occurred, and we have specialist officers who are trained in supporting victims through the investigation process.

If you need support, visit the Samaritans website or call 116 123.

The National Association for People Abused in Childhood (NAPAC) offers support to those who have suffered abuse or neglect as children. Visit their website or call 0808 801 0331.