Abstract: An emergency lighting system comprising light units and sensors, such as heat detectors, smoke detectors and motion detectors, operable to activate the light units. In the preferred embodiment, the light units are operable to adopt a selected one of at least two illuminated stated depending on the state of the sensors. Each illuminated state may involve the display of a symbol, text message or illumination pattern such as an arrow or a warning indicator, and/or may involve the emission of a respective illumination colour. The emergency lighting system may be associated with a set of stairs in order to illuminate the stairs when activated.