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.

Responsibilities

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.

Qualifications

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.

Essential skills

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 lifecycles, including Secure by Design practices, requirements definition, and traceability to technical controls.
Practical understanding of cybersecurity and safety standards.
Strong communication and stakeholder engagement skills, with the ability to liaise confidently across engineering, programme delivery, assurance, and regulatory audiences.
Ability to produce high-quality documentation, including risk assessments, technical guidance, assurance artefacts, and audit-ready deliverables.
Familiarity with UK cybersecurity regulations and sector guidance, including the NIS Regulations, CNI expectations, and industry-specific frameworks.
Capable of leading technical discussions and delivery planning across client, supplier, and internal teams.
Adaptable and delivery-focused, with the ability to balance long-term assurance needs with in-flight project delivery realities.

Desired skills

Knowledge of safety-critical system design and the interaction between safety and cybersecurity requirements.
Familiarity with tools and platforms used for engineering governance and requirement traceability.
Involvement in cybersecurity audits or regulatory reviews, including evidence preparation, control mapping, and client/regulator interaction.
Understanding supply chain security considerations, including software and hardware assurance, secure procurement, and third-party risk management.
Exposure to incident response planning, resilience testing, or crisis management in OT environments.
Ability to support or guide the creation of cybersecurity architecture documentation, reference models, or patterns for OT systems.

Experience

Experience in cybersecurity roles, focused on operational technology (OT), control systems, or industrial environments.
Proven track record in delivering cybersecurity outcomes within complex infrastructure or engineering programmes, in the UK rail sector or other safety-critical transport domains.
Demonstrated experience leading or coordinating cybersecurity efforts across multidisciplinary teams involving engineering, IT, operations, and assurance.
Hands-on experience implementing and assuring security controls in OT environments, including legacy systems, SCADA platforms, and hybrid IT/OT networks.
Familiarity with UK cybersecurity regulations and sector-specific standards such as TS 50701, IEC 62443, and ISO/IEC 27001.
Experience integrating cybersecurity requirements into systems engineering lifecycles, design reviews, and programme governance frameworks.
Prior involvement in client or regulator-facing roles, including technical reviews, risk assessments, assurance documentation, and compliance submissions.
Background in working within secure or regulated delivery environments, including understanding of information classification, access control, and physical security interfaces.
Experience mentoring or supporting the development of junior cybersecurity engineers or consultants.
Experience contributing to internal capability development, including mentoring, methodology evolution, or pre-sales support.
Practical experience working within or alongside regulated Critical National Infrastructure (CNI) sectors