There is discussed a location system for locating the position of a mobile communications device that communicates with a communication network using wireless signals. The location system includes a receiver which detects a wireless signal transmitted between the mobile communications device and a base station forming part of the communication network, and a processing means which processes the detected wireless signal to extract identification information for the mobile communications device. The extracted identification is stored in a data store in association with data indicative of the base station. The processing means and the data store are independent from the communication network, and therefore do not affect the operation of the mobile network.