CCTV camera (upper left) in a London Underground station. A tube train can be seen underneath the camera. London Underground has CCTV (Closed- Circuit Television) in 95% of stations. Smart software, called Intelligent Pedestrian Surveillance system (IPS), has been developed to help in the analysis of the images. It compares images from each CCTV camera with pictures of the empty station, analysing each pixel to pick out differences between the two images. Clusters of pixels, which could be objects or people, are tracked and behavioural oddities, such as a pixel cluster remaining on a platform after many trains have passed, are highlighted.