Open access. Night-time confinement is the practice of routinely locking patients in their rooms at night unless there is a contrary clinical indication. It is used in high-secure psychiatric hospitals. This article argues in favour of this practice on the basis of realistic medicine, an individual human rights based approach, the principles of mental health legislation in Scotland and England and cost effectiveness. This is not an academic debate. There is a real danger that those advocating against night-time confinement, if successful, will at best make little difference to the lives of our patients as they sleep, and at worst may hugely impoverish their lives because of reduced daytime activities.