OT Security Architect

OT Security Architect
£680 P/D
6 MONTH CONTRACT
OUTSIDE IR35
The OT Security Architect leads the discovery phase at a nominated comparator plant, establishing the security architecture direction for the facility. This is a hands-on, outcome-focused role requiring deep OT security expertise and the ability to translate complex, multi-vendor environments into clear, actionable architecture.
Key Responsibilities
Lead discovery at a nominated comparator plant, assessing OT security tooling, configuration, architecture, and alignment with NIST SP 800-82 and the Purdue Model.
Own the capability and control map, documenting reuse, extend, and new decisions, supported by clear rationale and evidence.
Identify and validate regulatory, hosting, connectivity, OEM, and other environmental constraints, maintaining a divergence register where requirements cannot be met.
Develop the MVP security architecture recommendation, including security patterns, dependencies, design decisions, and exceptions requiring client approval.
Define the sequenced delivery roadmap, implementation scope, dependencies, and acceptance criteria for the subsequent build phase.
Work closely with engineering, operational technology, infrastructure, and OEM stakeholders to ensure the proposed architecture is practical, scalable, and implementable.
Produce clear, high-quality architecture documentation and communicate technical recommendations to both technical and senior stakeholder audiences.
What We're Looking For
Essential
Deep, hands-on OT/ICS security architecture experience across industrial or critical infrastructure environments.
Expert knowledge of NIST SP 800-82 and the Purdue Model, with proven experience applying these principles to target-state OT architectures.
Strong knowledge of IEC 62443, including zone and conduit modelling and the application of security principles within industrial environments.
Experience developing capability and control maps, divergence registers, architecture decision records, and other structured architecture artefacts.
Proven ability to assess and validate regulatory, operational, technical, and environmental constraints within complex OT environments.
Strong High-Level Design (HLD) and architecture documentation skills, with the ability to produce deliverables independently.
Experience working with OEMs and technology vendors across complex, multi-vendor OT environments.
Strong stakeholder engagement and communication skills, with the ability to translate complex technical requirements into clear architectural decisions.
Desirable
Experience within manufacturing, pharmaceutical, or life sciences OT environments.
TOGAF, SABSA, or equivalent enterprise architecture certification.
ISA/IEC 62443 certification.

Work arrangement
Yes