Provision of services over a common delivery platform such as a mobile telephony network

One embodiment of a system for providing services to subscribers of a network supports the provision of a plurality of different services to multiple subscribers. A first processing unit provides a first execution environment for a first set of software applications and a second processing unit provides a second execution environment for a second set of software applications. A data structure is provided for storing data associated with subscribers of the system, the data structure providing a common identity for association with a subscriber which is recognized by all processing units of the system. This provides a common user repository which simplifies the provision of services and the authentication processes within the system.