People who have mental health crises while attending emergency departments (EDs) require immediate assessment and management, and ED staff must be prepared to meet the specific needs of this client group. This article gives an overview of the public psychiatric emergency assessment tool (Wright et al 2008), which is used by, for example, the Lancashire Constabulary to share information with healthcare professionals. By using the tool, practitioners can organise and structure the information they acquire during patient assessments, and from accompanying carers, paramedics, or police. They can then pass this information on to mental health specialists.