Embodiments of the invention are concerned with method and a system for event processing in a communications network, and are suited to coordinating the provision of services in response to service initiation triggers. Embodiments are particularly applicable for use in controlling operation of service nodes, each of which is arranged to provide a particular service in a mobile network, or a fixed network or a combination of the two. More specifically, embodiments of the invention provide event processing apparatus for use in processing service initiation request messages in an event processing system, the apparatus being connectable to a plurality of service nodes from which a subscriber is able to receive service during processing of a network event, each said service node being capable of transmitting a service response message in response to a service request message, the apparatus comprising a function arranged, on receiving a first service initiation request message sent by a serving node in a network currently involved in processing of said network event, to control operation of at least some of said plurality of service nodes involved in processing of the same network event, wherein the function is arranged to modify at least one said service initiation trigger and to formulate a service request message on the basis of said modified service initiation trigger. The service nodes can include a gateway node providing access to a plurality of further service nodes, such as those configured in accordance with the Open Services Architecture, beyond the gateway. In operation, the apparatus can be used to monitor for receipt of service response messages, service initiation trigger messages, co-ordinate communication between the various services and serving nodes with which a given subscriber has registered for service.