Principal Software Engineer C++ / Unreal / Defence, Portsmouth

Principal Software Engineer
Portsmouth | Hybrid, 3 days onsite
75,000-85,000 plus bonus and benefits

Want to work on groundbreaking projects within the defence industry?

Are you a hands-on technical leader with strong C++ and Unreal Engine expertise and want to work at the forefront of complex, performance-critical software delivery within defence?

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 in the defence industry. 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% 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