Principal Software Engineer (C++ / Unreal Engine)

Principal Software Engineer Portsmouth | Hybrid, 3 days onsite £75,000-£85,000 plus bonus and benefits This Principal Software Engineer role is designed for a hands-on technical leader with strong C++ and Unreal Engine expertise, working at the forefront of complex, performance-critical software delivery. The role combines advanced engineering with genuine technical authority, shaping how simulation-driven and autonomy-focused systems are designed, built and evolved. The position sits within a fast-growing software and data science consultancy delivering end-to-end solutions across defence, energy, transport and health. You will work closely with subject matter experts and senior stakeholders on high-impact programmes spanning modelling and simulation, autonomy, geospatial systems, synthetic environments and digital twins. This is a true principal-level role. You will remain deeply technical while setting direction, leading teams and acting as the technical authority across projects. What you will be doing * Leading the design and delivery of complex software solutions using C++ and Unreal Engine * Acting as technical lead across modelling and simulation, wargaming and autonomous systems * Applying mathematical and computational techniques to solve real-world problems * Owning key technical decisions across architecture, tooling and performance * Mentoring engineers and enabling high-performing delivery teams * Delivering technical consultancy engagements and leading selected projects * Building trusted relationships with customers and stakeholders * Supporting bids, proposals and technical reporting What you will bring * Extensive experience, typically 15+ years, delivering high-performance software * Proven technical leadership at Principal or Technical Lead level * Strong hands-on expertise in C++ and Unreal Engine * Background in simulation, autonomy, robotics or game-engine-driven environments * Experience working with large, complex codebases and performance constraints * Strong stakeholder management, communication and influencing skills What's on offer * Salary up to £85,000, flexible for exceptional technical leaders * 7 percent employer pension contribution * Vitality private healthcare * 25 days holiday with the option to buy or sell additional days * Life assurance * EV salary sacrifice scheme * Discretionary bonus linked to company performance * Structured mentoring and ongoing technical development