This disclosure concerns systems and methods for implementing location based services in communications networks. In one example, when the GMLC of a telecommunications network receives a request for the location of a mobile terminal, an SMLC is interrogated to obtain therefrom, if available, data indicative of the location of the relevant mobile terminal. The mobile terminal may be caused to selectively switch between a GSM radio access network and another access network if no location information is derivable from one of the access networks currently used by the device.