Security & Infrastructure Engineer (Defence AI scaleup)
We're looking for a reliable, experienced Security & Infrastructure Engineer (3–7 years in IT, cloud and security) to join our growing defence AI company in central Oxford, helping our teams stay productive, cyber‑compliant and protected as we scale. We develop and deliver mission‑critical unmanned aircraft subsystems, so reliability, problem‑solving skill and adaptability really matter.
This role sits at the intersection of IT operations, cloud infrastructure, and cyber security. You will work closely with a fractional Security Lead, deputy CTO, COO, IT manager plus other external CISO and consultants as relevant. You will be supporting delivery of a structured security programme while ensuring day‑to‑day systems remain secure, reliable, and efficient.
This is a hands‑on role suited to someone who enjoys both solving operational IT issues and implementing modern security controls in a fast‑paced, high‑assurance, advanced environment. You will play a key role in transitioning the company toward a security‑first infrastructure model.
How you will make an impact
- Security & Infrastructure: Implement and maintain secure, scalable IT and cloud infrastructure; support rollout of the Microsoft security ecosystem (Defender, Intune, Entra, Purview, etc.); configure and maintain identity, access control, and endpoint security; improve logging, monitoring and alerting capabilities.
- Security Programme Delivery: Support implementation of Cyber Essentials Plus, ISO27001‑aligned controls, Defence security requirements (e.g., DEFSTAN‑aligned environments); help maintain diverse assets globally (Linux, Windows, Mac); security control policy development; continuous security improvements.
- IT operations: Administer and support Microsoft 365, Google Workspace, cloud infrastructure (AWS/Azure), internal tools (Slack, Docker, etc.), providing incident response, troubleshooting and technical service delivery.
- Engineering & DevOps Support: Work with engineering teams to deliver secure development environments, AI / embedded device security, secure lab and flight trial environments.
To succeed in this role, you must have:
- 3–7 years of hands‑on experience in IT, cloud infrastructure and security with potential to grow into security leadership.
- Experience administering cloud environments (AWS, potentially Azure / hybrid / local / other).
- Experience with Microsoft 365, Google Workspace, Docker, Slack, virtual machines, AI LLM tools.
- Experience with security frameworks such as ISO27001, NIST.
- Experience managing Linux, Windows, macOS environments using endpoint management tools such as Intune.
- Experience with networking tools such as Cloudflare, Unifi or Cisco.
- Experience with Defender XDR, Microsoft Purview, Sentinel or similar cyber data security tools.
- Competency in incident response, investigation, vulnerability remediation.
- Ability to obtain and maintain a UK Security Check clearance.
- Willingness to work on site 4 days per week.
- Alignment with our ways of working: clear & concise communication; structured thinking to bring clarity from incomplete or imperfect information; high organisation, capacity and ownership to juggle multiple priorities; commercial awareness to apply judgment, not just follow procedures; growth mindset and positive energy.
It is a plus if you also have:
- Experience in designing IT systems from the ground up.
- Relevant security qualifications or certifications such as CISSP.
- Competency in DevOps, embedded systems security.
- Experience in aerospace, defence, or regulated environments.
- Familiarity with DEFSTAN‑style assurance requirements.
- Experience in tech startups working with engineering teams, requirements, engineering devices (IoT, AI cameras, embedded devices…) and environments.
- Military Background.
By joining us, you'll have:
- The ability to make a measurable difference in the creation of cutting‑edge technology in a rapidly growing start‑up.
- Fast‑paced environment with a world‑class, positive, talented, and high‑achieving team.
- Forward‑thinking, supportive culture with company retreats and strategic alignment.
- World‑class growth opportunities and training resources including self‑development days; an opportunity for drone pilot training.
- Merit‑based compensation.
- 25 days holiday + UK bank holidays.
- Medical insurance.
- Team socials.
- A variety of perks that are evolving: Free Monday team lunch, Cycle2work scheme, annual subscription allowance.
Security clearance
Due to the sensitive nature of some of our work, candidates must be able and willing to obtain and maintain the necessary security clearance for this role.
Location
This is an office‑based role in Oxford. You'll work alongside leading engineers, AI specialists, and industry pioneers, contributing directly to cutting‑edge advancements in autonomous technology.
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