Hundreds of thousands of adults with mental health problems are not being given the appropriate support when taken into police custody, a charity has claimed.
An analysis of police figures showed trained volunteers known as 'Appropriate Adults' were only used in around 45,000 detentions and voluntary interviews of adults a year - despite there being 1.4 million in total, and 280,000 involving someone who was mentally vulnerable.
The study, carried out by the National Appropriate Adult Network after being asked to do so by Home Secretary Theresa May, also found police custody sergeants had reported difficulties in getting hold of appropriate adults out of hours.
Some areas did not have any formal plan for mentally ill adults at all. Ms May said she would review the charity's findings, calling the situation "not acceptable".
The chief executive of the National Appropriate Adult Network, Chris Bath, said recommendations in the report included a national framework for the provision of appropriate adults, a statutory duty on police officers to secure one, and improvements to police training and record keeping on vulnerable adults.