In one embodiment, there is provided a mobile communications device comprising: a processor; a communications subsystem operable to exchange signals with a wireless network; a storage element having application modules and data stored thereon, the data comprising at least user application data associated with the application modules and service data including data for establishing communications with the wireless network; and a security module operable to detect policy messages received by the device, and to perform a security action if a first policy message to enforce a first data protection policy is received and a subsequent policy message to enforce a second data protection policy is not received within a predetermined duration from the time at which the first policy message is received; wherein the security action comprises erasing or encrypting at least some of the data on the storage element.