A telecommunications network service has a number used to route a call through the network which includes means of identifying a call-related message passed over a separate unrelated message path. An Intelligent Network Architecture as above may be used with a telecommunications system including a Virtual Private Network (VPN), the VPN comprising a plurality of Private Branch Exchanges (PBX), each PBX having a connection to a public telephone network and to an Intelligent Network (I.N.) within the system wherein, when a VPN call is initiated by a user connected to a PBX the PBX sends a message via the I.N. to the destination PBX, also a connection is made between the PBX and the local exchange and a message is sent from the local exchange via the I.N. to a VPN Service Point, whereupon the Service Point establishes a connection, via the I.N. between the user local exchange and the destination PBX.