Security Engineer III in Welwyn Garden City

As a Senior Security Engineer in Tesco’s Innovation Engineering team, you will pioneer next generation security capabilities that proactively protect a retail ecosystem serving millions of customers. You will combine deep engineering expertise with an innovation mindset to build production-grade solutions that leverage applied Artificial Intelligence (AI), automation, and modern development practices to strengthen Tesco’s cyber defence.

This role sits at the point where ideas become real: you will design, build, test, and operationalise capabilities that measurably reduce risk and improve resilience. You will also act as a technical leader, setting engineering direction, raising standards, and influencing across diverse security and technology teams with a customer-first focus. In the immediate term, you will focus on the needs of our Cyber Threat Intelligence and Detection Engineering teams.

This team operates as an innovation incubator for cyber defence capabilities: rapidly exploring ideas, validating them through prototypes and experiments, and ensuring the strongest concepts graduate into secure, reliable production services. Depending on the nature of the capability, ownership may either remain within this team or transition to the most appropriate long-term service owner once the solution is proven and operationally ready.

You will work closely with our Security Automation Engineering team to build a shared roadmap of opportunities to deliver across Cyber Defence, ensuring we build and/or buy the best technologies to deliver our vision.

You will be responsible for:

• Architect and deliver innovative security capabilities: Design and build high impact security solutions that improve Tesco’s defensive posture, from concept through to production operation, with measurable outcomes.
• Embed AI augmented security engineering: Apply AI and automation to accelerate and improve security outcomes, ensuring solutions remain safe, explainable, and fit for operational use.
• Lead modern engineering approaches for cyber defence: Use contemporary software development practices to turn ideas into secure, production-ready capabilities, with a focus on automation, experimentation, maintainability, and scale.
• Champion engineering excellence: Establish secure, test-driven approaches, code quality standards, automated testing, version control discipline, and repeatable release patterns to ensure innovation is reliable and maintainable.
• Share knowledge and inspire others: Showcase your work, build understanding, and foster excitement around the solutions you develop so innovation can scale beyond the team.
• Validate effectiveness and resilience: Design evaluation strategies and functionality testing so controls work as intended, regressions are prevented, and defensive improvements are demonstrable over time.
• Influence and enable change across teams: Collaborate with security and technology stakeholders to drive adoption of new capabilities, communicate trade offs clearly, and create inclusive ways of working that help teams succeed.

You will need:

• Demonstrable expertise in applied AI for cyber defence, including identifying high value use cases, translating them into engineering work, and delivering outcomes safely with human accountability and appropriate guardrails.
• Exposure to technical AI architecture & implementation, with the ability to design, review, and refine AI enabled systems without sacrificing security or operability.
• Demonstrable understanding of technical security architecture, including producing and defending design decisions, selecting appropriate patterns, and anticipating operational and threat-driven failure modes and designing against them.
• Strong programming capability, evidenced by building production grade tools, automations, or services with clear structure, maintainability, and secure engineering hygiene.
• Demonstrable understanding of secure & test driven engineering, applying automated testing, secure design principles, and disciplined change control to protect reliability whilst enabling speed.
• Strong capability in evaluating security solutions, including setting clear technical requirements and success criteria, assessing control effectiveness, and validating solutions against realistic operational and threat-informed conditions.
• Demonstrable understanding of core cyber defence technology, including how telemetry, detection/response tooling, and automation ecosystems fit together to deliver measurable defensive outcomes.
• Strong data analytics & insights capability, including selecting meaningful measures, analysing trends, and using evidence to prioritise work and communicate impact.
• Strategic thinking & problem solving, balancing innovation with operational reality, and making sound decisions in ambiguous or fast moving contexts.
• Communication & influencing, able to explain complex technical concepts to varied audiences, align stakeholders, and drive decisions and adoption.
• Embracing and enabling change, demonstrating leadership through change, helping teams modernise practices and adopt new capabilities without destabilising delivery.
• Curiosity, learning, and research mindset, actively exploring emerging technologies and adversary trends, then translating learning into practical, scalable engineering improvements.
• Commitment to inclusion & belonging, with evidence of fostering supportive, psychologically safe engineering environments.

Desirable Skills:

• Awareness of AI governance, compliance, and responsible AI principles, including privacy, data protection, and risk management considerations.
• Evidence of contributions to the profession (community involvement, publications, talks, mentoring, open-source work, or recognised learning achievements).
• Familiarity with Tesco’s core technology landscape and retail technology context, connecting technical risk to customer experience and operational continuity.
• Demonstrable understanding of development lifecycle practices, especially in environments with CI/CD and automation.
• Exposure to technical interviewing, supporting hiring through practical assessments and structured evaluation.
• Experience managing backlogs and delivering iteratively using Jira and product delivery practices.
• Familiarity with and experience using operational collaboration tooling such as Zendesk & xMatters in the context of incident workflows and on call engagement.

What’s in it for you?

We’re all about the little helps. That’s why we make sure our Tesco colleague benefits package takes care of you – both in and out of work. Annual bonus scheme of up to 20% of base salary. Holiday starting at 25 days plus a personal day (plus Bank holidays). Private medical insurance. 26 weeks maternity and adoption leave at full pay, followed by 13 weeks of Statutory Maternity Pay or Statutory Adoption Pay, we also offer 6 weeks fully paid paternity leave. Free 24/7 virtual GP service, Employee Assistance Programme (EAP) for you and your family, free access to a range of experts to support your mental wellbeing.

About Us: You might know us as a supermarket, technology company or even for our award-winning mobile network. Truth is, we’re all of those things, and much more. Our colleagues work with one goal in mind, helping to make every day a little better for our customers, colleagues and communities all over the world. No two customers are the same, neither are our colleagues.

At Tesco, we champion a balance that lets you thrive both in and out of work. Spend 60% of your week collaborating with colleagues at our office locations or local sites and the rest remotely. Whether you're just kicking off your career, juggling passions, or navigating big life events, we're here to support you. We always welcome a conversation about flexible working, so talk to us throughout your application about how we can support.

We're proud to be an accredited Disability Confident Leader, where everyone’s welcome. That’s why we commit to providing a fully inclusive and accessible recruitment process. If you need support with your application, please reach out for more information. And if you're interested in joining our team but don't tick every box, don't let that hold you back from applying.