It is the intention of the Mental Handicap Services of the Chichester Health Authority to implement a discrete electronic alert system for some of the patients who are incapable of consent. An activator, similar to the bar code in a library book, or tag in a clothing store will be kept in a pocket of the patient's clothing. When a patient who carries the activator walks through a magnetic field at the door of the unit, it will trigger a bleep held by the nurse in charge to inform him/her that this particular patient is leaving.