A new approach to safety assurance is proposed when using a service-based approach. Many safety systems today are used in a service context, i.e. used as part of an operational scenario involving collaborative working of the systems, people, processes (and contracts and subcontractors). It is only when the whole picture is considered that the overall safety position can be made. Such safety-related services can be of many forms, for instance Air Navigation, Fleet Maintenance or e-Prescribing and can be found in diverse domains, such as Transport, Defence, Energy or Healthcare. The new approach and methodology is based on service concepts where the Service Catalogue, Contract, Service Level Agreements (SLA) and Capability of the Service Provider(s) become the cornerstones of the assurance position; contrary to traditional systems assurance there is less need to "open the box" to examine the technology components and their construction. Of note is that many safety-related Information Technology systems have moved to an IT service provision model where established safety standards and guidelines don't readily apply; something new is needed. This paper describes the current progress in developing methods for assuring these key elements and how an assurance argument may be constructed for the Customer-Facing Services and the whole Service-Orientated Architecture (SOA). The ongoing work of the SCSC Service Assurance Working Group is a key input for this work.