The Care Quality Commission has issued a formal warning to Avon and Wiltshire Mental Health Partnership over levels of staffing at Blackberry Hill Hospital in Bristol.
It followed an unannounced inspection of three wards at the Fromeside Unit in December. The medium secure unit provides specialist care and treatment for adults with mental disorders, which may mean that they are at significant risk of harming themselves or others.
Inspectors found that the unit was failing to comply with the national regulation on staffing and did not have not enough qualified, skilled or experienced staff to meet people's needs.
More top news
Finnish media say several people have been wounded in a stabbing in the city of Turku in western Finland.
The National Farmers' Union, RSPCA and Marine Conservation Society want a nationwide ban to protect wildlife.
A Dorset man has launched a social media appeal to find his 7-year-old cousin who is missing in Barcelona after yesterday's terror attack.