Principal System Design Engineer

As a Principal Systems Design Engineer , you will be a key engineering lead shaping the architecture and design of advanced C4I systems for critical defence programmes. This role seeks leadership elements for an experienced systems engineer who thrives on solving complex challenges, influencing strategy, and mentoring others. You will drive innovation, ensure technical excellence, and deliver integrated solutions that meet demanding operational requirements. Lead system architecture and design for complex, mission-critical defence systems, translating operational concepts into robust solutions. Define and implement technical strategy, ensuring alignment with programme objectives and future capability needs. Guide design reviews and ensure technical integrity throughout the lifecycle, including integration of specialty disciplines (Safety, Security, Human Factors, ILS, Training). Conduct trade studies, performance modelling, and evaluate emerging technologies to inform strategic decisions. Mentor junior engineers and engage with senior stakeholders, including MoD representatives, to influence programme-level decisions. Click here for the full job description Essential: Extensive experience in systems engineering and system design leadership. Proven ability to resolve complex design challenges and make strategic trade-offs. Strong track record of leading cross-functional teams and engaging specialist disciplines. Expertise in structured design methods and requirements management. Exceptional communication skills—able to present confidently at senior-level reviews. Skilled in producing high-quality technical documentation and delivering to schedule. Proficiency in Microsoft tools (Word, Excel, PowerPoint, Visio). Proven track record in system architecture and design for complex, mission-critical systems. Experience across the full engineering lifecycle (requirements, design, integration, verification). Desirable: Deep understanding of network architectures, OSI model, and open standards. Familiarity with Open and Military Standards and compliance frameworks. Experience with Model-Based Systems Engineering (MBSE), SysML and structured design methodologies. Knowledge of TOGAF or NATO Architecture Framework. Awareness of Safety, Security, and ILS processes within defence programmes. Experience working with or familiarity with AI/ML models is preferred. Salary for this position is £59,200 to £80,000, depending on experience plus our excellent flexible benefits package. We offer hybrid working - for this role ideally we are looking for an average of 2 days per week per month on site. We pride ourselves in being a great place to work with a shared sense of purpose, offering impressive benefits:  A compressed nine-day fortnight and compressed hours - which means every other Friday off.  A personalized career development plan, alongside regular progress reviews - supporting and valuing your progression within the…