RISHI SUNAK must end the “inhumane” imprisonment of the disabled, charities said today as thousands of people with autism and others with learning difficulties remain stuck in mental health hospitals.

In an open letter, the National Autistic Society and Mencap called on the Prime Minister to reform outdated laws and pass the Mental Health Bill into law before the next general election.

Last year, the government published a draft of the Bill, proposing changes to the Mental Health Act that include better protection for autistic people and those with learning difficulties.

Under current legislation, such individuals are defined as having mental health conditions and can be detained in secure units.

This leaves them without access to appropriate support and can lead to physical and mental deterioration, the charities warn.

NHS data shows that, since the Bill was introduced over 450 days ago, 2,135 autistic people or people with learning disabilities have been admitted to hospital — an average of about four a day.

Leo Andrade, whose a 28-year-old son with autism and a learning difficulty was detained under the Act for six years from 2013, is among those campaigning with the charities for legislative change.

She said that Stephen had been locked up at a site more than 70 miles away from their home and, where he was overmedicated, restrained and traumatised.

“I battled for years to get him out,” Ms Andrade said.

“Stephen doesn’t have a mental health condition, so should never have been detained in a mental health hospital.

“What my son desperately needed was the right environment and support to help him to be happy and enjoy his life in his community. He was failed by the system.”

The open letter can be signed by members of the public on the charities’ websites.