A police investigation into 24 cases of reported rape and 18 incidents of sexual assault at a psychiatric hospital has not led to any prosecutions.

The alarming revelations at Littlebrook, a 106-bed hospital for patients with acute conditions in Dartford, led to just one agency nurse being suspended from duty and reported to the police.

The figures emerged followed a freedom of information request sent to Kent Police from the producers of Channel 4 documentary 'Locked Away - Our Autism Scandal'.

It airs tonight and will tell the stories of autistic patients detained in mental health units.

These include one of a young female patient, who claims she was groomed by a male support worker for several months before being raped in a part of the hospital that was not monitored by security cameras.

Danielle Attree is autistic and has spent half her life locked up in psychiatric institutions.

During this time, the 25-year-old said she has been held in solitary confinement and sleeping on a mattress on the floor for almost two years.

She was also chemically coshed, violently restrained by teams of adults and raped.

Danielle's mother, Andrea, said her daughter's case is only the tip of the iceberg.

She said that despite being moved to a specialist centre in the north of England, Danielle's mental health has deteriorated and her eating disorders intensified, resulting in substantial weight loss and forced feeding.

"Maybe I'm better off dead," Dannielle texted her mother when saying goodnight recently. "I hope I don't wake up again."

Kent Police data reveals that of 24 reported rapes at Littlebrook, they failed to identify a suspect in half the cases while the remainder - along with 15 reported sexual assaults - were dropped for 'evidential difficulties'.

In one alleged case of sexual assault, 'further action resulting from the crime report' was taken up by another official body or agency.

Littlebrook is run by Kent and Medway NHS and Social Care Partnership Trust, one of the country's biggest mental health trusts with 33 sites.

In 2016, The Care Quality Commission praised the trust's services as outstanding for care and effectiveness - but marked it down as "requires improvement" for safety with issues over maintenance, repairs and staff raising concerns to their managers.

Chief executive Helen Greatorex, said they could not discuss individual cases but encouraged reporting of any concerns by both patients and staff.

She said: "We take the safety of our service users, their loved ones and our staff extremely seriously and do not tolerate any form of sexual harassment or misconduct

"Whilst none of the reports made to the police resulted in criminal action, we can confirm that we took immediate action against one individual, an agency nurse. We removed them from duty and reported them to both the police and their employer."

Ms Greatorex added that although Littlebrook had assisted autistic people in crisis due to the lack of specialist provision, there needed to be far more specialist provision rather than relying on acute mental health hospitals to fill the glaring gaps in services.

After an inspection between November and December 2020, the health watchdog found it was delivering safe care to adult and psychiatric patients but issues remain over nutrition with some relying on takeaways.

It found wards for adults of working age and psychiatric intensive care units delivered "safe care" and "staff managed risks well".

Inspectors said formal complaints were managed well with patients aware of their rights and how to complain although it was not always clear how informal complaints were documented and handled.

Kent Police said tackling rape and sexual offences was a top priority, and it works with the Crown Prosecution Service to get offenders into court whenever possible.

Det Supt Mark Weller said: "We carry out a full and thorough investigation into every incident reported to us. Victims' welfare is at the heart of everything we do."