CROSS DOMAIN SME RATE: £700 - £850 a day LOCATION: Preston, Lancashire DURATION: 12 Months SECTOR: Defence & CNI CLEARANCE: Active DV Required THE OPPORTUNITY We are working exclusively with a globally recognised prime defence contractor to identify a subject matter expert in Cross Domain Solutions (CDS) for a complex, high-assurance programme based in Preston. This is a senior, technically demanding role at the heart of a programme operating across multiple security domains and classification levels. You will provide deep technical expertise across the design, implementation, and assurance of cross domain transfer mechanisms - working closely with architects, security teams, and accreditors to ensure solutions meet the stringent requirements of a highly classified defence environment. WHAT YOU'LL BE DOING // Acting as the programme's technical authority on all Cross Domain Solution matters // Defining and owning CDS architecture, design patterns, and security controls // Leading the evaluation, selection, and integration of accredited CDS products and technologies // Working with security architects and accreditors to achieve and maintain system accreditation // Providing SME input to risk assessments, HMG/MOD security reviews, and technical audits // Developing and reviewing CDS-related security documentation (RMADS, SyOps, TRA) // Advising on data guard design, content filtering, and information flow policy enforcement // Liaising with NCSC, DSTL, and other government bodies as required by the programme // Supporting transition and integration activity across classification boundaries // WHAT WE'RE LOOKING FOR // Active, current Developed Vetting (DV) clearance - non-negotiable // Demonstrable SME-level expertise in Cross Domain Solutions within a UK defence or government environment // Deep understanding of HMG information assurance policy, JSP 440, JSP 604, and SPF requirements // Hands-on experience with accredited CDS products (e.g. Nexor, Owl, Forcepoint, or equivalent) // Strong understanding of data guard architectures, content inspection, and policy enforcement engines // Familiarity with MOD/DSTL accreditation and risk management processes (RMADS, ISO 27001) // Experience producing and reviewing security case documentation for high-classification systems // Ability to engage credibly with senior stakeholders, accreditors, and government technical authorities // Prior experience on UK defence programmes at SECRET or above is highly desirable