Principal Software Engineer (AI/ML) in Luton

Salary Range: £54,000 - £70,000

Leonardo UK operates a grade-based salary framework with broad bands. The salary range shown reflects the approved grade band for this role, or a narrower hiring range published within that band, and is benchmarked against the external market. Exceptions above the standard range are managed through governance controls to protect internal equity.

Your Impact

Are you a software engineer with a working knowledge of Artificial Intelligence (AI) and Machine Learning (ML)? Are you interested in developing software for some of the most cutting-edge defence and aerospace projects in the UK? If the prospect of developing software for projects such as a sixth-generation stealth fighter jet or a revolutionary Laser Directed Energy product excites you, then Leonardo would like to hear from you.

Leonardo is seeking to recruit Senior or Principal Software Engineers with an interest in Artificial Intelligence and Machine Learning to join our well-established software community within our Electronics UK business. Successful candidates will contribute to the delivery of leading-edge solutions for challenging civilian and military projects.

Leonardo has a significant interest in exploiting AI/ML technologies. In this role, you will support our systems engineers on research projects while developing deployable software solutions that leverage AI/ML capabilities.

What you’ll bring

You will have experience of, and a passion for, AI/ML. You should hold a degree in Computer Science, Engineering, or a related technical discipline, combined with practical experience in delivering high-integrity software products within a regulated environment.

• Industry experience working on Agile projects across the full software life cycle.
• Proficiency in machine learning frameworks such as PyTorch and TensorFlow, as well as tools for model integration.
• A strong foundation in AI/ML, including transformer architectures, tokenisation, embeddings, and fine-tuning large language models (LLMs).
• Experience building scalable pipelines, including APIs, vector databases, retrieval-augmented generation (RAG), and orchestration frameworks.
• Experience curating datasets, managing embeddings, and ensuring security, privacy, and responsible AI practices.
• Experience in prompt engineering, with the ability to design, test, and systematically improve prompts, while measuring the accuracy, bias, and robustness of LLM outputs.
• Awareness of agentic workflows involving AI agents that can plan, reason, and take autonomous actions.
• Awareness of governance, security, and compliance considerations relating to data management and AI deployment.
• Awareness of mathematical libraries used for signal, image, and data processing.
• Awareness of high-performance computing and the challenges associated with parallel processing.

This list is not exhaustive, and we are keen to hear from you even if you do not meet every requirement. The most important attribute is a willingness to learn and develop.

Security Clearance

This role is subject to pre-employment screening in line with the UK Government’s Baseline Personnel Security Standard (BPSS). An additional range of Personnel Security Controls referred to as National Security Vetting (NSV) may apply, this could include meeting the eligibility requirements for The Security Check (SC) or Developed Vetting (DV).

Why join us

At Leonardo, our people are at the heart of everything we do. We offer a comprehensive, company-funded benefits package that supports your wellbeing, career development, and work–life balance. Whether you're looking to grow professionally, care for your health, or plan for the future, we’re here to help you thrive.

• Time to Recharge: Enjoy generous leave with the opportunity to accrue up to 12 additional flexi-days each year.
• Secure your Future: Benefit from our award-winning pension scheme with up to 15% employer contribution.
• Your Wellbeing Matters: Free access to mental health support, financial advice, and employee-led networks championing inclusion and diversity.
• Rewarding Performance: All employees at management level and below are eligible for our bonus scheme.
• Never Stop Learning: Free access to 4,000+ online courses via Coursera and LinkedIn Learning.
• Refer a friend: Receive a financial reward through our referral programme.
• Tailored Perks: Spend up to £500 annually on flexible benefits including private healthcare, dental, family cover, tech & lifestyle discounts, gym memberships and more.
• Flexible working: Flexible hours with hybrid working options. For part time opportunities, please talk to us about what might be possible for this role.

For a full list of our company benefits please visit our website. Leonardo is a global leader in Aerospace, Defence, and Security. Headquartered in Italy, we employ over 53,000 people worldwide including 8,500 across 9 sites in the UK. Our employees are not just part of a team—they are key contributors to shaping innovation, advancing technology, and enhancing global safety.

At Leonardo we are committed to building an inclusive, accessible, and welcoming workplace. We believe that a diverse workforce sparks creativity, drives innovation, and leads to better outcomes for our people and our customers. If you have any accessibility requirements to support you during the recruitment process, just let us know.

Be part of something bigger - apply now!