It has been common clinical practice for staff members to make an application to a mental health tribunal (the First-tier Tribunal (Mental Health) in England or the Mental Health Review Tribunal in Wales) on behalf of a patient detained in hospital for psychiatric treatment who may lack capacity to make that application, for example in dementia in-patient settings. Following a series of cases in the Upper Tribunal, such practice may not be appropriate and there is now a risk that the application will be struck out. It is important that clinicians are aware of developments in case law and therefore we provide guidance on how clinicians should approach applications to the tribunal and the assessments of capacity that may be required.