There is a crisis in police cells across the country, and it is not to do with crime, according to senior officers. The police say they regularly have to detain mental health patients who should be dealt with by psychiatric professionals. The problem... (more) is so bad that police estimate it takes twenty five per cent of their time. With exclusive access to police custody, reporter Paul Kenyon discovers a world of self-harm and suicide attempts which is stretching police to their limits. But he also spends time in a mental health unit, where they say police are dealing with fewer mental health patients than they used to. Nevertheless, one of the UK's most senior police officers tells Panorama that enough is enough: it is time the police refused to detain any at all, and got on with their job of tackling crime.