Principal Systems Engineer

Smiths Detection is a global leader in threat detection and screening technologies supporting aviation, ports & borders, defence, and urban security. With 5 R&D centres, 21 global offices, and 7 manufacturing sites, our 3,000 brilliant minds have spent over 40 years at the frontline, developing solutions that protect society from explosives, prohibited weapons, contraband, toxic chemicals, and narcotics. Every minute of every day, our technology and people help make the world a safer place.

We are seeking a delivery‑focused Principal Systems Engineer to act as the systems lead on a UK defence programme. This role is not focused on hands‑on mechanical or electronic design. Instead, it centres on owning requirements, verification, and compliance, and ensuring all engineering outputs align precisely with customer and regulatory expectations. You will be the person who knows the system inside out and can confidently stand behind it with customers.

This role suits someone who is:

• Highly detail‑oriented
• Comfortable working independently
• Happy spending time reading, checking, and validating documentation
• Confident engaging directly with customers in a clear, factual manner

You will work closely with engineering, science, test and production teams, but your focus will be on requirements, verification, and evidence, rather than active design. Responsibilities will include:

• Owning system requirements and ensuring full traceability through verification
• Managing and delivering the systems compliance matrix
• Compiling and reviewing verification evidence across Technology
• Comparing test reports, design documents and certificates against hundreds of requirements
• Delivering the systems input into formal design reviews, including Critical Design Reviews
• Coordinating systems engineering deliverables and schedules across the programme
• Acting as a senior technical contact for the customer, providing clear and honest responses
• Managing systems work packages with suppliers and sub‑contractors

Strong background in systems engineering, requirements management, and verification is essential. Experience working in regulated or safety‑critical environments is also important. A solid understanding of the systems V‑model is required, along with clear written and verbal communication skills. Candidates must be eligible to obtain UK Security Clearance.

Defence experience is helpful but not required. Candidates from aerospace, rail, automotive, or other regulated industries are very welcome.

Working pattern: Hybrid working, with typically 2 days per week on site in Hemel Hempstead. Flexible working arrangements considered, including part‑time, for the right candidate.

Qualifications:

• Requirements management tools such as DOORS (experience helpful but not mandatory)
• Verification & validation planning and execution
• Producing and reviewing:
• Design specifications
• Verification reports
• Certificates of design / conformity
• Familiarity with technical and design reviews
• Ability to quickly learn and apply standards (e.g. Defence Standards, EMC, safety)
• Exposure to MBSE / SysML is a plus, but not essential

We believe that different perspectives and backgrounds are what make a company flourish. All qualified applicants will receive equal consideration for employment regardless of color, religion, sex, sexual orientation, gender identity, national origin, economic status, disability, age, or any other legally protected characteristics. We are proud to be an inclusive company with values grounded in equality and ethics, where we celebrate, support, and embrace diversity.