Systems Engineer+SC cleared role+Hybrid working 2/3 days a week in Reading+Inside IR35+ 80 - 83 ph We are seeking an experienced Senior Systems Engineer to lead the delivery of model-based Product Security digital capabilities across a complex, regulated engineering environment.Reporting to the Product Owner - Systems Engineering, you will define and implement the reference architectures, toolchains and technical baselines that enable end-to-end traceability across the Digital Thread - from security objectives and threat modelling through to verification, validation and assurance evidence.This role replaces document-centric practices with authoritative, model-based security engineering across the full product lifecycle.Key ResponsibilitiesDeliver and continuously improve Product Security digital toolchains, including:Threat and risk modelling (STRIDE, STPA-Sec, TARA, attack trees)Security requirements and controls modellingSBOM and vulnerability managementCryptography and key management governanceConfiguration/change controlVerification and validation orchestrationSecurity/assurance case evidenceDefine Product Security reference architecture and Digital Thread integrationsOwn roadmap, backlog and delivery planning aligned to enterprise prioritiesEstablish governance, data standards and model quality controlsLead vendor engagement, technology evaluations and service performanceDrive adoption of model-centric security engineering across programmes and suppliersEnsure alignmen