Abstract: The invnetion provides secure access to applications such as intranet access and corporate e-mail systems from mobile terminals such as cellular telephones and Personal Digital Assistants (PDA) using Wireless Application Protocol (WAP) by using an identifier that is unique to the mobile terminal (either the handset itself or the Subscriber Information Module (SIM) card that is used in the handset). This is passed to the authentication systems used by the service provider after the conventional verification of username and password details. If the identifier matches the record held in the authentication database then the service provider returns a number of user-specific options, such as corporate e-mail, intranet access, inventory or ordering systems.