Principal Software EngineerPortsmouth | Hybrid, 3 days onsite£75,000-£85,000 plus bonus and benefitsThis 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* B