Senior AI Engineer

VodafoneThree: Senior AI Engineer

Location: Newbury+ *Hybrid working

Working Hours: Full time 37.5 hours per week, from Monday to Friday 

*Hybrid We believe that through collaboration and connection with our colleagues we can achieve great things. Our hybrid working approach allows our people to work both in the office and at home, providing the flexibility and resources you need to succeed in your role. We don't require you to be in on specific days; instead, we ask people to come into the office 2-3 days each week. You should work with your line manager to understand what their expectations are for you, your specific role and your team.

Who We Are

We’re here to build a network the UK can count on – one that connects people, places and potential. Because no matter where you live, what your background is, or how you get online – we think everyone deserves the same chance to stay connected, and with VodafoneThree, that future’s being built – today.

We’re creating more than the UK’s best network. We’re helping close the digital divide, empower communities and drive meaningful progress.

We believe that everyone should feel they belong. Whoever you are and whatever your story, there’s space for you here. We’re building a workplace where different perspectives are welcomed, voices are heard, and everyone feels safe to show up as themselves.

You’ll join a team that genuinely cares – about each other, about our customers, and about the future we’re building. From day one, you’ll be welcomed, valued and encouraged to bring your whole self to work.

Why VodafoneThree

Join us and you’ll be at the heart of change. That means building responsibly, investing sustainably and creating opportunities that last.

We’re not just expanding connectivity; we’re reimagining what a connected nation looks like. With £11bn invested in 5G and digital infrastructure, your work will directly power businesses, services, and communities across the country.

You’ll work on real challenges, with real impact, across every corner of the country. Wherever you join us, whatever your role, you’ll be helping to build a future that works better for everyone.

We move at pace, because what we’re building matters – and we’re learning as we go. We’re proud of the progress we’ve made, but we’re just getting started.

Join us at the heart of our business in Corporate, one of the central support functions that underpin our business and keep us moving forward. We provide centralised support, expertise and guidance across our UK and Group operations, continuing to build on our success and trailblazing the way to our next stage of digital growth.

As Senior AI Engineer you will be the technical practitioner within the AI engineering function, leading complex technical delivery of production-grade AI applications whilst mentoring and directing the engineering team.

You will be building AI applications that work at scale: designing and implementing retrieval-augmented generation systems, agent workflows, automation tools, and prompt engineering patterns. Partnering closely with the AI Product Manager (who defines requirements and prioritisation), whilst collaborating with Data Science and ML Engineering functions on model integration.

• Lead technical delivery of complex AI application projects from architecture through production deployment
• Design and build production-grade AI applications including RAG systems, agent frameworks, intelligent automation tools, and decision-support workflows
• Establish and maintain application-level patterns around prompt engineering, guardrails, human-in-the-loop workflows, and content filtering
• Mentor and provide technical guidance to AI Engineers, supporting their growth and capability development
• Evaluate emerging AI technologies, frameworks, and architectural patterns for practical applicability within the organisation
• Ensure non-functional requirements are met across AI applications: latency, cost-per-interaction, safety, content filtering, accessibility, and graceful degradation
• Collaborate with enterprise architecture to maintain alignment with organisational standards and constraints
• Manage technical debt pragmatically, making informed recommendations on build-versus-integrate-versus-buy decisions
• Contribute to governance, compliance, and risk management for AI product releases
• Drive code quality standards, testing practices, and engineering discipline within the AI engineering function

Job Requirements, Knowledge & Experience

• Degree in computer science, software engineering, or related discipline (or equivalent professional experience demonstrating equivalent knowledge).
• Strong software engineering fundamentals: good working knowledge of software design and architecture patterns, proficiency in Python and TypeScript/JavaScript, API design, automated testing, and CI/CD practices.
• Proven track record building AI-powered applications in production environments at scale.
• Hands-on experience with large language models, foundation models, and modern AI application frameworks (LangChain, Semantic Kernel, or equivalent).
• Practical experience designing and implementing RAG architectures, vector databases, embedding strategies, and retrieval optimisation.

Additional Information

Worried that you don’t meet all the desired criteria exactly?

We know that everyone is unique, with multiple aspects to their identity and different experiences behind them. We are passionate about Inclusion for All and creating a workplace where everyone can thrive, whatever their personal or professional background. If you’re excited about this role but your experience doesn’t align exactly with every part of the job description, we encourage you to apply as you may be the right candidate for this role or another role, and our recruitment team can help you see how your skills fit in.

What we offer

We care about our people’s success by offering great pay, bonuses, up to 28 days off plus bank holidays, and paid time for charity work. You can personalise our benefits for you and your family, like discounts, vouchers, a pension plan and loads more. We help with your career through our amazing learning tools and top-notch parental leave policies.

Closing Date: 4th July 2026

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Need to know

We are regulated by the Financial Conduct Authority and all offers of employment for this role are subject to background checks, including criminal (DBS) and financial checks to meet the regulators standards.

We believe everyone should have the opportunity to interview for a role that matches their skills. In collaboration with our Talent, Diversity & Inclusion teams and our employee-led DEI Networks, we identified a range of reasonable adjustments to help you feel comfortable and perform at your best self during the interview process. If you require any reasonable adjustments or have an accessibility request as part of your recruitment journey, for example, extended time or breaks in between online assessments, a sign language interpreter, or assistive technology, please contact your recruiter directly or email jobs@three.co.uk for guidance.

We use AI in different parts of our business to boost innovation, improve efficiency, and create new opportunities. We know many candidates use AI to fine-tune their CVs or prepare for interviews, but what we really care about is your unique experiences and achievements.

During the interview, we want you to rely on your own knowledge and skills to show us who you really are—your personality, creativity, and abilities. Above all, we’re looking for authenticity and can’t wait to get to know the real you.

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