A doctor had vulnerable children stripped naked, put in a straitjacket and injected with a “truth serum” so he could sexually assault them, police have been told.

Kenneth Milner, who died in 1976, is thought to have carried out the abuse at Aston Hall psychiatric hospital in Derbyshire. Police said that if he were alive today, there would be “sufficient evidence” to interview him for offences including rape, indecent assault and child cruelty. Fourteen allegations of rape were made against him.

At least 65 children were abused while Milner was medical superintendent at Aston Hall from 1954 until the 1970s, a report by Derbyshire police claims. A separate review by the local safeguarding board found he had “great power, control and influence” over troubled boys and girls.

A number of former child patients at the hospital told detectives about a similar “treatment” they endured, known as “narco-analysis”. This involved interviewing patients in a drug-induced state in order that they recall and disclose thoughts and feelings they would normally conceal.

The report said: “This consisted of stripping naked, bathing, administering of medication by injection – sodium amytal – before dressing in a heavy jacket described as similar to a ‘straitjacket’.” The victims said they were laid down on a single mattress and asked questions about abuse they suffered, usually sexual, involving family members.

A doctor would put a gauze mask over their face and drip liquid on to the mask, commonly believed by the patients to be ether, police were told.

“Patients’ recollections of what happened vary; some describe themselves as having been so stupefied that they were unable to accurately say, others recall sexual touching including attempted rape. Many patients recall soreness around the genitalia, dampness and the presence of unknown liquids,” the report said.

It noted that “this type of procedure would not be acceptable within today’s medical standards. It is questionable as to whether it was acceptable during the period in question, particularly in the treatment of young people”.

As well as the alleged sexual abuse, there were claims of a patients being hit while trying to resist treatment, one having her head repeatedly forced under water, and another having her hair repeatedly pulled to force her to take medication.

Another said she woke with her hands bound after being drugged, and complained to a nurse of soreness between her legs. The nurse slapped her around the head and told her she must have a urine infection.

The vast majority of the allegations were made against Milner. Other staff members accused of physical abuse have either been eliminated from the inquiry, are also dead or are unable to be identified.

Aston Hall hospital began in 1925 as a hospital for people with learning disabilities, but it later became a treatment centre for children with learning disabilities and mental health issues. Children in care from across the country were placed there by local authorities, both for long-term treatment and weekend care.

Detectives interviewed 114 alleged victims, who are mostly aged 49 to 79 and were patients at Aston Hall between 1954 and 1979. They live across the UK and some as far afield as Australia.

More than 50 local authorities sent children to Aston Hall and lawyers believe there could be thousands of victims.

Although Milner is dead, Derbyshire police said they would continue to interview former patients and help them access care, treatment, counselling, therapy and support.