Network access control

An access control system for controlling access by wireless terminals to a wireless telecommunications network, the access control system comprising: a database storing the identities of a set of wireless terminals belonging to the telecommunications network; a configurable store for storing a supplementary access value indicative of whether terminals that do not belong to the telecommunications network may access the network; and an access control unit for receiving an access request message indicating the identity of a wireless terminal and in response to that message accessing the database and/or the store to permit access by the wireless terminal to the wireless telecommunications network if: a. the identity of the wireless terminal is present in the database; or b. the supplementary access value indicates that terminals that do not belong to the telecommunications network may access the network.