We work in a national mental health diversion service; this gives us a good overview of a range of mental health services across the country. We are writing to draw attention to a new development in a range of adult mental health services around the country (we have had experience of this in several separate geographical areas throughout the UK) - the ‘opt-in letter’. When referring patients with an apparent episode of psychosis (for example, delusional beliefs that one is the Messiah), the response of the receiving service has been to send the patient an impersonal standard letter, stating that someone has expressed concern about their mental health and offering them the chance to ‘opt in’ to an appointment. If the patient does not take advantage of this opportunity the case is then closed. We are extremely concerned about the appropriateness of this as a response to patients with severe insight-disabling illnesses. We can find nothing in the scientific literature to support this development (apart from in psychotherapy services to reduce the non-attendance rate, where the client group has a very different diagnosis and presentation), and are concerned that this represents a dangerous and perverse form of crude demand management. We would be interested to hear of the experience of others, and whether there are colleagues who would defend the practice.