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. 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. Provide expertise on OT protocols, SCADA systems, field devices, and network architecture relevant to the client's operational landscape. 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. 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. 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. Familiarity with UK cybersecurity regulations and sector guidance, including the NIS Regulations, CNI expectations, and industry-specific frameworks. 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. 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, ideally 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. 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. Practical experience working within or alongside regulated Critical National Infrastructure (CNI) sectors. What do I need before I apply You must have the right to work in the UK