There was a "systemic failure to protect people" by the owners of a hospital at the centre of abuse allegations involving vulnerable adults, care watchdogs have said.
The Care Quality Commission (CQC) has published its findings following an inspection of services provided at Winterbourne View, owned by Castlebeck Care Ltd, in Bristol.
The report comes after the BBC's Panorama filmed patients being pinned down, slapped, doused in cold water and repeatedly taunted and teased despite warnings by whistleblower Terry Bryan. Mr Bryan, a senior nurse, had alerted the care home's management and the CQC on several occasions, but his concerns failed to be followed up.
After considering a range of evidence, CQC inspectors found Castlebeck Care had failed to ensure that people living at Winterbourne View were adequately protected from risk, including the risks of unsafe practices by its own staff.
It said: "There was a systemic failure to protect people or to investigate allegations of abuse. The provider had failed in its legal duty to notify the Care Quality Commission of serious incidents including injuries to patients or occasions when they had gone missing."
It added that staff did not appear to understand the needs of the people in their care and said "some staff were too ready to use methods of restraint without considering alternatives".
Winterbourne View, which had 24 patients, was closed down last month. The watchdog said the review began as soon as it found out Panorama had gathered evidence, including secret filming, to show the serious abuse of patients at the centre.
Following the TV documentary, the CQC issued an unreserved apology for failing to act on warnings of abuse but director of operations Amanda Sherlock said on Monday that it was incorrect that it "failed to act", adding that: "CQC has already acknowledged that we would have acted earlier if the evidence from the television report had been made available to us."
In response to the report, Castlebeck chief executive Lee Reed said: "As soon as the company was made aware of the appalling misconduct of staff at Winterbourne View, we alerted the police and other relevant authorities. We then took immediate remedial steps to safeguard the welfare of all our service users. This work is ongoing, and is our absolute priority."
Avon and Somerset Police have arrested a 12th person in connection with the inquiry into the mistreatment of patients at Winterbourne View. A spokeswoman confirmed that a 27-year-old man from the South Gloucestershire area had been arrested under the Mental Capacity Act and released on police bail pending further inquiries.