According to the World Health Organisation during their lifetime more than one quarter of all individuals will develop one or more mental or behavioural disorders. Given prevalence data like this it is not surprising that wherever they reside on the planet many persons suffering from a mental disorder, or as is more commonly termed in popular parlance a mental illness, are likely to come into contact with police at some stage in their lives. Indeed, research conducted in a number of countries suggests that about 10 per cent of all community police work involves some form of interaction with a person with a mental illness. From a police perspective these encounters are not only frequent but also often sensitive and challenging.