Job Title: Senior/Principal Platform Systems Mechanical Engineer Job Location: Barrow-in-Furness, Onsite This position requires full-time on-site presence. Please speak to your recruiter for further details. Salary: Competitive Who we are: Join BAE Systems and you''ll be part of something bigger. As a valued member of our global colleague network, you''ll bring your unique skills and perspectives to help pioneer progress and protect what matters most. You''ll be trusted to play your part in delivering the advanced, technology-led defence, aerospace and security solutions of tomorrow - shaping a safer future, for all of us. What you will be doing: In this role, you will support the development and delivery of mechanical platform systems, ensuring robust design evidence is generated to support safe and effective solutions. You will contribute to testing and commissioning activities, support issue resolution, and work closely with engineering teams to maintain design intent across complex submarine programmes. You will also mentor junior engineers, contribute to technical outputs, and engage with stakeholders to support successful programme delivery. Core Duties: Develop and deliver design evidence to justify safe and effective engineering solutions, ensuring customer confidence in system designs Specify and support the build of prototypes, products, and systems suitable for testing and validation activities Provide timely resolution of defects and issues, ensuring corrective