Abstract: A head up display system for a motor vehicle includes a sensor, display means for forming a video image from the signals received from the sensor and a projection system for projecting the video image onto the windscreen of the vehicle, the projection system including a mirror for deflecting the optical path of the projected image, said mirror being located directly in front of a driver of the vehicle at a level outside the normal field of view of the driver through the windscreen, the mirror being arranged; in a head up display mode, to direct the projected image onto the windscreen; and in a non-head up display mode, to permit direct viewing of the video image at a level outside the normal field of view of the driver through the windscreen.