A method of managing identities for use in a mobile telecommunications device in a telecommunications network, the method being performed by a subscriber identity module and comprising: triggering an identity management process in the subscriber identity module; detecting one or more parameters comprising a Mobile Country Code, MCC, and a Mobile Network Code, MNC, of a currently available mobile telecommunications network; in the identity management process, searching an identity database in the subscriber identity module, wherein each record in the identity database comprises an identity and additional identity information for each identity, and wherein each said identity comprises an International Mobile Subscriber Identity, IMSI, and the additional identity information includes the one or more parameters; in the identity management process, selecting an identity when a first record comprising the one or more parameters detected is found in said searching, wherein selecting an identity comprises searching through an ordered list of records in the identity database to find a first record in which the MCC and the MNC match the MCC and MNC detected, and selecting the identity of said first record, and wherein if there is no record in which the MCC and the MNC match the MCC and MNC detected, selecting an identity comprises selecting a first record in which the MCC matches the MCC detected, and selecting the identity of said first record; and in the identity management process, modifying an active identity of the mobile telecommunications device to be the selected identity when the active identity is not already the selected identity. triggering an identity management process in the subscriber identity module; detecting one or more parameters comprising a Mobile Country Code, MCC, and a Mobile Network Code, MNC, of a currently available mobile telecommunications network; in the identity management process, searching an identity database in the subscriber identity module, wherein each record in the identity database comprises an identity and additional identity information for each identity, and wherein each said identity comprises an International Mobile Subscriber Identity, IMSI, and the additional identity information includes the one or more parameters; wherein each record in the identity database comprises an identity and additional identity information for each identity, and wherein each said identity comprises an International Mobile Subscriber Identity, IMSI, and the additional identity information includes the one or more parameters; in the identity management process, selecting an identity when a first record comprising the one or more parameters detected is found in said searching, wherein selecting an identity comprises searching through an ordered list of records in the identity database to find a first record in which the MCC and the MNC match the MCC and MNC detected, and selecting the identity of said first record, and wherein if there is no record in which the MCC and the MNC match the MCC and MNC detected, selecting an identity comprises selecting a first record in which the MCC matches the MCC detected, and selecting the identity of said first record; and wherein selecting an identity comprises searching through an ordered list of records in the identity database to find a first record in which the MCC and the MNC match the MCC and MNC detected, and selecting the identity of said first record, and wherein if there is no record in which the MCC and the MNC match the MCC and MNC detected, selecting an identity comprises selecting a first record in which the MCC matches the MCC detected, and selecting the identity of said first record; and in the identity management process, modifying an active identity of the mobile telecommunications device to be the selected identity when the active identity is not already the selected identity.