In the 21st century, safety assurance in the defence industry in the UK has had to evolve to encompass the provision of services in safety-related environments. When considered in the context of upkeep and maintenance of assets ranging from the 800-year-old HM Naval Base Portsmouth to the state-of-the art HMS Queen Elizabeth Aircraft Carrier, how such services are safely managed is paramount. This paper sets out an approach to Product Safety management when the product is the “provision of a service”. In managing our diverse portfolio across HM Naval Base Portsmouth, BAE Systems has implemented an approach to assurance where service providers develop their own service assurance case bounded to the unique, mostly repetitive services they provide. When new work-packages arrive, a service providing organisation undertakes an efficient review of their current safety assessment for change or validity of their assurance case. This offers the Accountable Product Owner assurance for the whole work package. Of importance is the organisation’s recognition of their accountability for the services they provide throughout the period the service is being delivered. The work underpinning this paper has contributed to the ongoing efforts of the SCSC Service Assurance Working Group and the guidance being developed.