IT Manager in Milton Keynes

Greenjets is developing next-generation aerospace systems designed to deliver step-change performance, sustainability, and sovereign capability. As we scale into defence and government programmes, we are establishing secure, accredited environments capable of handling Secret and TS documentation. We are looking for an experienced IT Manager to design, build and operate this capability from the ground up. This is not a maintenance role. It is an opportunity to architect and own a defence-grade secure environment inside a high-growth engineering company.

The Role

You will lead the design, implementation and ongoing operation of IT systems capable of safely handling classified material, aligned with MOD and defence prime requirements. Working closely with engineering, operations and leadership teams, you will ensure our secure environments are robust, compliant and scalable — without slowing down innovation.

Key Responsibilities

• Architecting and deploying IT systems capable of handling Secret (and where required TS) classified information
• Designing secure network segmentation, access controls and controlled environments
• Implementing and maintaining controls aligned to NIST 800-171 and NIST 800-53
• Leading accreditation preparation, audit readiness and ongoing compliance
• Developing governance frameworks for secure document handling and information security
• Managing suppliers and secure technology partners
• Supporting defence customers and accrediting authorities directly

What Success Looks Like

Within your first 12–18 months:

• A fully operational, accredited secure IT environment
• Strong audit performance with no critical findings
• Clear, documented and scalable security processes
• Trusted relationships with MOD and defence prime stakeholders

Experience Profile

Essential

We are specifically seeking individuals who have operated in defence environments and understand the realities of classified systems.

• 5+ years in IT or information security roles within:

• A defence startup
• A defence prime MOD or equivalent government defence organisation

• Hands-on experience implementing NIST 800 frameworks
• Experience operating within classified environments (Secret or higher)
• Experience preparing systems for accreditation or formal audit
• Strong understanding of secure infrastructure and endpoint hardening

Technical Expertise

• Identity and access management in secure environments
• Secure cloud or on-prem classified networks
• SIEM and continuous monitoring
• Data loss prevention and encryption
• Secure document management systems

Desirable

• CISSP, CISM or similar certifications
• Experience with UK MOD accreditation processes
• Experience building secure IT environments from first principles

Behaviours

• Comfortable balancing startup pace with defence rigour
• Able to translate standards into practical, working systems
• Detail-oriented and documentation disciplined
• Credible with engineers, executives and government stakeholders
• Calm under scrutiny and audit

Why Join Greenjets?

This role underpins our ability to win and execute sovereign defence programmes. The secure systems you build will directly enable mission-critical aerospace technology. If you want to build secure infrastructure that genuinely matters — and do it in a high-growth, engineering-led environment — we’d like to hear from you.