The operator of a residential hospital has apologised unreservedly and suspended a number of staff following allegations that carers routinely abused vulnerable adults with learning difficulties.
Police have also launched an investigation and arrested four people after undercover footage of the apparent misconduct at Winterbourne View, in Bristol, was recorded by investigators from BBC's Panorama programme.
The hospital's operator Castlebeck said it was "distressed" and "shocked" by the accusations that workers physically and verbally abused residents on a daily basis.
The secret recordings, filmed between February and March this year, appear to show carers punching and slapping vulnerable adults, dousing them in cold water, and pinning them to the ground with chairs.
Thirteen members of staff including two managers have been suspended and three men and one woman had been arrested by Avon and Somerset police, according to the BBC.
All patients have been moved to safety.
Clinical psychologist Andrew McDonnell said he was shocked by the footage and labelled some of the examples captured on film as "torture". He told the programme that basic techniques for dealing with patients with challenging behaviour were ignored.
After viewing one excerpt, he said: "This is not a jail...people are not here to be punished. This is a therapeutic environment. Where's the therapy in any of this? I would argue this is torture."
Company officials said they had not seen the footage ahead of the programme, but were made aware about its contents on May 12.
"Castlebeck immediately notified the police, Care Quality Commission (CQC), the local Safeguarding team, commissioners of the service, other relevant authorities, and the families of the patients named in the allegations," said a statement released by the firm. "Staff alleged to have behaved inappropriately were suspended and reported to the police, who are now investigating."