OT Cybersecurity Engineer

Overview

Expleo is a trusted partner for end-to-end, integrated engineering, quality services, and management consulting for digital transformation. We help businesses harness unrelenting technological change to deliver innovations that provide a competitive advantage and improve everyday life worldwide. As part of the Expleo Digital and Emerging Technology (DET) team, you will report to the Head of Cybersecurity and join our established Cybersecurity Practice.

We are seeking a highly experienced OT Cybersecurity Technical Lead to support a strategic client engagement in the UK rail sector, with a focus on the security of operational technology and safety-critical infrastructure. In this role, you will lead the technical assurance and delivery of cybersecurity activities across a programme of work involving legacy and modern OT systems, rail-specific technologies, and industrial control components.

You will work closely with engineering and operational teams to embed cybersecurity across the lifecycle, ensuring alignment with UK rail regulations, industry standards, and best practices.

• Act as the cybersecurity technical lead within a key UK rail sector client engagement, focusing on protecting operational technology (OT) and safety-critical systems.
• Provide hands-on technical leadership to guide the secure delivery of client-specific systems and solutions, ensuring alignment with project requirements, sector standards, and regulatory obligations.
• Collaborate with client engineering and programme teams to integrate cybersecurity into system design, deployment, and ongoing operations.
• Define cybersecurity requirements within the client’s environment, including rail-specific systems, legacy OT, and modern industrial platforms.
• Support developing and delivering security risk assessments, threat models, and control frameworks following the relevant standards.
• Contribute to the production and review of assurance artefacts, including security cases, risk registers, control implementation evidence, and compliance documentation.
• Provide expertise on OT protocols, SCADA systems, field devices, and network architecture relevant to the client’s operational landscape.
• Engage regularly with client stakeholders, suppliers, and technical teams to ensure effective collaboration and secure outcomes across the delivery lifecycle.
• Mentor and support other team members embedded within the client account, ensuring technical consistency and alignment to Expleo’s delivery standards.
• Participate in knowledge sharing and capability development activities within the Cybersecurity Practice, contributing insights from the client engagement.

• A degree (or equivalent experience) in Cybersecurity, Systems Engineering, Electrical/Electronic Engineering, or a related technical discipline.
• Recognised cybersecurity certifications: CISSP, CISM, CISA, GICSP, SABSA, or equivalent.
• Technical certifications or training aligned to OT security: IEC 62443, GIAC GRID/GICSP, SCADA/ICS security, or vendor-specific OT platforms.
• Familiarity with rail sector security and safety standards is highly desirable.
• Understanding of relevant UK regulatory frameworks, including NIS/NIS2 Regulations and UK CNI expectations.
• Additional certifications or practical experience in Secure by Design, systems assurance, or control systems architecture are advantageous.
• Evidence of continued professional development aligned with OT security trends, critical infrastructure resilience, and systems assurance practices.

• In-depth understanding of operational technology (OT) environments, including SCADA systems, field devices, industrial protocols, and control network architectures.
• Firm grounding in cybersecurity principles for critical infrastructure, including threat modelling, risk analysis, defence-in-depth, and zero-trust architectures.
• Demonstrated ability to define, implement, and assure security controls across complex OT/IT systems within large engineering or infrastructure programmes.
• Experience integrating cybersecurity into engineering life cycles, including Secure by Design practices, requirements definition, and…