Controlling portable digital devices

A system for controlling usage of a portage digital device (14) having an audio and/or image data recording or capture function (12). Operation of said data recording or capture function is inhibited when the portable digital device is located in a specific geographic location or region (10). A method of controlling usage of a portable digital device in a communications network, is also describedwhich includes the steps of: receiving a signal over the network at the device; analysing the signal at the device to determine whether usage of the device should be controlled, and controlling usageof the device in accordance with the result of the analysis. The method also includes the steps of: providing a list of locations where control of the application is to be restricted; comparing information regarding the location of the device with the location: on the list, and if the location of the device is present in the list, producing a result indicating that usage of the device is to be controlled.