Principal Systems Engineer

Principal Systems Engineer (SC/DV Preferred) | UK Nationwide We are seeking a Principal Systems Engineer to support the development and governance of complex system interfaces within a secure engineering environment. This is a high-impact role where you will shape system architecture, define interfaces, and ensure robust technical control across multiple stakeholders. SC Clearance is required (DV highly preferred) and candidates must be British nationals. The role is UK-wide (flexible location) with occasional travel to Reading. Key Responsibilities Develop Interface Relationship Diagrams (IRDs) using SysML Block Definition Diagrams in Sparx Enterprise Architect (EA) Produce and maintain Architecture Definition Documents (ADDs) Create and manage detailed Interface Registers Develop and maintain Interface Control Documents (ICDs) Lead monthly Interface Control Meetings (ICMs) following ICD issuance Ensure interface consistency, traceability, and alignment with system architecture Act as technical authority for interface governance and resolution of interface issues Collaborate with cross-functional engineering teams and stakeholders across the lifecycleKey Skills & Experience Strong background in Systems Engineering (Principal / Senior level) Proven experience in interface management (IRDs, ICDs, ADDs) Strong working knowledge of SysML modelling Experience with Sparx Enterprise Architect (EA) or similar tools Ability to manage complex system architectures and multi-stakeholder environments Confident leading technical governance and interface control meetingsSecurity & Eligibility SC Clearance required (DV preferred) Must be a British citizenLocation UK nationwide (flexible working) Occasional travel to ReadingWhy this role? This is a chance to play a key architectural role in a complex, secure engineering environment, shaping system interfaces and influencing design decisions at a senior level. Millbank Holdings Ltd is an equal opportunities employer committed to creating an inclusive and diverse workforce. We welcome applications from all suitably qualified individuals, regardless of background, and encourage candidates from underrepresented groups to apply.   We are proud to be a member of the Disability Confident Scheme, and we are committed to ensuring an accessible and supportive recruitment process for everyone. If you require any adjustments at any stage, please let us know and we’ll do our best to accommodate. Millbank operates as both an Employment Agency and an Employment Business