UK police forces dealt with nearly 300,000 incidents involving people with mental health issues last year, figures show.
New data obtained under the Freedom of Information Act show 296,773 incidents were recorded in 2016, with South Wales Police having the highest number of any force at 38,712.
This was followed by Nottinghamshire Police, which registered 19,973 incidents with a mental health code, and the Police Service of Northern Ireland, which registered 19,668.
The lowest number of reported incidents was for North Wales Police at 766.
The data were obtained by the think tank Parliament Street and shared exclusively with the Press Association.
Danny Bowman, mental health spokesman for Parliament Street, said: "These findings reveal the shocking numbers of mental health issues currently being dealt with by police forces across the country.
"It's time to recognise that Britain needs a better funded strategic plan to ensure people who are suffering with mental health problems are properly cared for by specialist health services."
Paul Farmer, chief executive of the mental health charity Mind, said: "Mental health is core police business."
He said police officers are often the first people to come into contact with "people in mental health crisis" and it was important they had the right support, including from NHS mental health services, to ensure people get the help they need.
He called for further investment to help people before they reach crisis point, adding: "Getting people the right help as early as possible means people can manage their mental health, are less likely to end up in crisis and, ultimately, will reduce pressure on all emergency services."
A Government spokesman said: "People experiencing mental health crisis need the right care in the right place, not a police cell.
"We're investing £30 million in providing more alternative places of safety, have more than halved the number of people detained under a mental health section in a police cell in the last year and are entirely banning the use of police stations for this purpose for under 18s."