Principal Engineer - National Security AI

Principal Engineer/Hands-on Technical Lead

Permanent | £80,000 - £100,000 | South East (Hybrid)
SC clearance required or eligible

We are seeking a Principal Engineer to take ownership of technical delivery for Defence programmes. The role focuses on building AI-enabled capabilities in secure, air-gapped environments, combining hands-on software engineering with technical leadership to deliver high-assurance solutions.

You'll be working on some of the most exciting projects within Defence AI and LLM generation and deployment, delivering and integrating core products and working with the customers to build best in class systems for mission decisions.

Key Responsibilities

• Lead day-to-day technical delivery on Defence programmes
• Make architecture and design decisions for deployments into classified environments
• Write production code, conduct code reviews, and set engineering standards
• Translate programme requirements into technical plans, sprints, and deliverables
• Work closely with Defence stakeholders, delivery managers, and end users on site
• Manage technical risk, dependencies, and integration points across programme workstreams
• Mentor and develop engineers within the team
• Contribute to technical proposals, bids, and architecture documentation
• Support release management and deployment in air-gapped environments

Skills & Experience

• Significant experience as a senior or lead engineer delivering complex software in secure or regulated environments
• Strong ability to articulate architecture and integration concerns clearly
• Proficiency in Python and/or TypeScript (core stack)
• Familiarity with AI/ML integration patterns (model serving, RAG pipelines, vector databases)
• Understanding of secure development practices
• Experience working in fast-paced, scaling organisations
• UK-based with willingness to travel to sites as required
• Hold or eligible for DV clearance

This is a high-impact role delivering nationally significant defence programmes with flexible hybrid working in the South East.