System, Method and Apparatus for allied individual services with application procedures or Sign-On Services

provides telecommunications system, the single sign-on services or services with a single logon procedure to a user who accesses selected service provider, wherein the user has a subscription at a first mobile network operator, said system comprising: - a first mobile network and at least a second mobile radio network; and - at least one of a plurality of service providers for providing services to subscribers of mobile networks, when the subscriber for a service provider have been authenticated by an authentication authority once at least; the system being characterized in that a cellular network of mobile network operators acting as the authentication authority, said cellular composite comprising the first mobile radio network and containing at least one second mobile radio network, and the following: - an authentication provider associated with the first mobile network as the only element of the composite, which a service provider is authorized to authenticate the user towards the least; and - an authentication broker to a particular one of the ...