Abstract: Lighting units (22) in a room (20) are controlled automatically and remotely in response to motion sensor modules (26) located to cover the area of the room (20). A sensor module (26) detecting movement transmits a radio signal to a controller module (28), which then transmits a corresponding control signal to the responder modules (24), causing them to switch their associated lighting units on and then increase their brightness to a preset level. The system includes an emergency lighting responder module (32) to switch on emergency lighting (34) if mains power fails and is also responsive to ambient light level. Each of the controller module (28), the sensor modules (26) and the responder modules (24) include a radio transceiver and all control and management signals are transmitted from location to location by radio. Other sensor modules (responsive to different variables) and responder modules may be added to build up a wireless building management system.