Principal Engineer - Human-Centric Technologies (Defence & Security)

The Role  

We have an opportunity for a Principal Engineer working with a particular focus on our defence and security clients. You’ll join a team of talented engineers and scientists designing, building, and testing intelligent, human-centric systems.  

As one of the senior technical voices in the team, you’ll be architecting the technical approach on our projects, setting the technical bar for others, and helping shape the work we deliver. As well as hands-on research and engineering, you’ll spend time with clients, using your expertise to win new projects as well as deliver them.  

Much of our defence and security work requires security clearance, so we ask for it up front. You won’t work exclusively in that sector, but a genuine interest in it matters to us.  

We offer a flexible approach to hybrid working, although some of the projects you will be working on will require full-time working in the office.  

What you’ll be doing  

• Designing and developing human-centric intelligent systems: technical frameworks and architectures that perceive, reason about, and adapt to human state, behaviour, and intent in real time using multi-modal sensing and contextual modelling.   
• Designing, protocolling, and running human subject studies, conducting empirical data evaluation, and synthesising scientific insights to inform and back technology design.   
• Conducting deep literature reviews across experimental psychology, cognitive science, and human factors, translating complex concepts into actionable engineering requirements.   
• Acting as technical lead and architect on our larger, more complex projects, owning the technical solution and the value it delivers to the client.   
• Develop proposals and costed work programmes, turning client problems into work we can win and deliver.   
• Setting technical direction and acting as technical reviewer across the department, with your advice sought by colleagues.   
• Steering internal capability, research, and demonstrators that keep us at the forefront of technology and open up new conversations with clients.   
• Mentoring engineers and scientists and conducting technical interviews to help us recruit and grow strong people.   
• Supporting and contributing to how the department works, improving our processes and technical standards.  

What you can bring 

 We are looking for an experienced technical lead, with the scientific and engineering breadth to guide the human-centric component of multidisciplinary work and the ability to work with our commercial teams to help create and win new work.   

• Extensive experience in applied cognitive science, human-computer/robot interaction, human factors, or related human-centric technology fields, including working on defence or security projects.   
• Extensive experience conducting human subject research: end-to-end experiment protocol design, running empirical studies, evaluating complex data sets, synthesising actionable insights, and navigating ethics committee processes.   
• Experience architecting the technical approach on complex projects and acting independently as the technical authority.   
• A strong undergraduate degree in a relevant technical or scientific subject, such as Cognitive Science, Psychology, Computer Science, Human Factors, or Neuroscience. A PhD in a relevant subject is welcome but not required; deep, demonstrable industrial expertise is what matters.   
• Strong technical capabilities in Python and relevant computational modelling tools.   
• Interest in working directly with clients and contributing to proposals and technical sales conversations.  

Because of where this role sits, holding (or being able to obtain) UK security clearance is essential. You must be eligible to obtain Security Check (SC) level security clearance (https://www.gov.uk/guidance/united-kingdom-security-vetting-applicant). You must be able to work in the UK without restrictions in accordance with UK National Law and be prepared to successfully undertake an appropriate level of UK National Security Vetting according to UK Government criteria.   

While not essential requirements, we would also be very interested if you have experience with any of the following:   

• Technical experience with AI/ML frameworks (e.g., PyTorch) and agentic workflows.  
• Technical exposure or experience in Brain-Computer Interfaces (BCI), neurotechnology, biosensing, or wearable augmentation/exoskeletons.  
• An established external profile: publications, conference talks, or shareable project credentials in relevant venues.