An inquiry found that patients were hit in the face, kicked, wrongly restrained, bathed in cold water and regularly deprived of fluids. One resident was tied up and locked in his room and a female nursing assistant told another patient: "I'll break your neck."
The hospital's trust is now recommending that staff who work with the elderly be vetted in the same way as those working with children.
An internal inquiry into the mistreatment found that at least 30 staff, including doctors and managers, had been bullied into silence. Beech House at St Pancras Hospital was closed within months of the problems coming to light. Three staff were sacked for gross misconduct in connection with the case and another retired but no police action is to be taken.
The mistreatment came to light when a member of staff asked to move jobs and eventually blew the whistle.
The inquiry found an atmosphere of intimidation had made it difficult for staff to report their concerns. But it also said that all the nurses on the 13-patient ward had "either perpetrated or knowingly supported the abuse of patients".
Announcing an action plan to improve mental health services for older people, the head of the health trust responsible apologised "unreservedly" yesterday to the patients and their families.
Dr Usman Khan, chair of Camden and Islington Community Health Services NHS Trust, said it had already begun to put into practice the lessons learnt from the internal inquiry, which produced 61 recommendations.
Among them is a proposal that staff working with the vulnerable elderly should be checked, as is the case with children. The report also called for a review of the disciplinary process. "The hearings exposed the way in which the regime of care at Beech House was largely and deliberately hidden from the relatives of residents, other clinicians and service managers," it said.
The report noted that what occurred at Beech House did not reflect the way in which care was provided to other patients at St Pancras.
A spokesman for the charity Help the Aged said it feared there were many more such cases in NHS hospitals.
"The Government must take immediate action to make sure that hospitals monitor and improve their standards of care of the elderly."