Lead Security Architect

Lead Security Architect (Defence Dev Sec Ops  / AI‑ML)

Client: UK Defence

Role: Lead Security Architect

Location: Portsmouth (hybrid:
50% remote / 50% onsite
)

Start: Approx.
24 Aug 2026

Contract end:
23 Nov 2026

Rate: £640-£700/day (Inside IR35) via FCSA‑approved umbrella

Clearance / nationality:
Active MOD SC required + Sole UK National

You’ll own the security architecture and assurance roadmap for AI/ML delivery across multi‑cloud and edge environments. You’ll ensure solutions align to UK Defence priorities and the client’s IT/cloud strategy, enabling secure multinational collaboration and repeatable, high‑assurance releases (including high‑side promotion pathways). You will lead the Secure by Design approach end‑to‑end.

• Lead security architecture and delivery across multiple AI/ML trials and use cases
• Chair security working groups and support tri‑nation collaboration
• Drive security visibility, outcomes, and senior stakeholder engagement
• Own threat and risk management
  , translating ambiguous requirements into sable controls
• Design classification‑aware architectures
  : trust boundaries, data flows, and cross‑domain guardrails
• Provide pragmatic security guidance for a complex programme (security as an enabler)
• Define and deliver the security roadmap across:
  • Dev Sec Ops operating model
  • Policy‑as‑code and automated control enforcement
  • Risk‑based CI/CD gates and release assurance
• Govern supply chain security (artefact signing, SBOMs, provenance) using SLSA‑style controls
• Improve delivery outcomes: reduced time‑to‑secure‑release, reliable promotion checkpoints, efficient supplier onboarding, and clear exec‑level risk reporting
• Mentor junior team members

• 5+ years in cyber security, including security architecture across multi‑cloud/edge
• Defence experience and familiarity with UK security expectations / guidance
• Active MOD SC clearance and sole UK nationality
• Certifications:
  
  CISSP (or equivalent) and TOGAF (or equivalent architecture framework)

• Adaptable, pragmatic, and positive‑treats security as a business/mission enabler
• Comfortable working in ambiguity and building clarity through controls, assurance and stakeholder management