The object was to develop and evaluate a new concentrated model of psychiatric diversion scheme at the magistrates' court, designed to maximize the potential of such interventions. A one-year prospective study was undertaken of a consecutive series of 264 referrals to the new diversion project at an Inner London magistrates' court, with concurrent examination of police station custody records, magistrates' court returns, hospital admission data and remand prison transfer records for an area with a population of 500,000. The results showed that this one scheme originated 12.8% of all the unrestricted hospital orders in England under section 37 of the Mental Health Act 1983, 4.2% of section 35 orders, and 6.4% of section 48 and 48/49 remand prisoner transfers. Of all arrests in the central London area, 0.46% were referred to the scheme, with 0.28% being admitted. The seriousness of the charge did not have a significant effect on whether or not admission was achieved (p = 0.5365). The new model is a powerful intervention in the assessment and diversion of mentally disordered offenders. Similar supra-district diversion centres may have a role to play in other areas, complementing other local diversion exercises, some of which might better be relocated to the police station.