The concept of public service is a twofold one: it embraces both bodies providing services and the general-interest services they provide. Public-service obligations may be imposed by the public authorities on the body providing a service (airlines, road or rail carriers, energy producers and so on), either nationally or regionally. Incidentally, the concept of the public service and the concept of the public sector (including the civil service) are often, wrongly, confused; they differ in terms of function, status, ownership and "clientele".
See:
General-interest services
Public service Charter
Services of general economic interest
Subsidiarity
Universal service