The Geotechnical Sub Alliance (GSA)

The Geotechnical Sub Alliance (GSA) is at the forefront of the Sizewell C nuclear power station development - one of the UK’s largest and most exciting infrastructure programmes.

We’re responsible for preparing the foundations of the entire site: designing and constructing cut‑off walls, retaining structures, soil improvements and more. Using advanced geotechnical engineering and world‑class construction technologies, this is a rare opportunity to contribute to a national project that will shape the UK’s clean‑energy future.

The Role

The Information Security & Assurance Officer is responsible for ensuring that GSA implements and maintains all mandatory information and cyber‑security controls required under the client Information Security Management Plan (ISMP), associated security documentation and governance agreements with parent companies.

The role provides assurance across corporate and project systems, oversees integration with client security operations, ensures subcontractor compliance, and leads the development and operation of a robust Information Security Management System (ISMS) aligned to ISO/IEC 27001. You will act as the central authority for information security governance, incident management and continuous improvement across the organisation.

What You'll Be Doing

• Governance & Compliance: Implement and enforce client ISMP requirements across GSA, including security assurance levels, export control, information classification and data‑handling rules. Maintain governance documentation, audit evidence and subcontractor security flow‑downs, and support client, partner and third‑party security reviews.
• Security Assurance & ISMS Ownership: Own and operate the ISMS, including policies, standards and procedures. Complete and manage required security and privacy assessments (e.g. TPSA, SRA, DPIA, ECIA), track remediation actions, review suppliers, and ensure alignment with UK GDPR, DPA 2018, NIS2 (where applicable) and sector‑specific standards.
• O365 & Technical Security Oversight: Provide assurance over O365 and core IT controls, including identity and access management, MFA, endpoint protection, logging, monitoring and baseline security configuration across office and operational locations.
• SOC Integration & Incident Management: Oversee security monitoring, log availability, alerting and incident response processes, ensuring effective integration with the client SOC and any managed security service providers. Lead or support incident response, root‑cause analysis and post‑incident reviews.
• Stakeholder Engagement & Awareness: Act as a trusted adviser to IT, project teams and business units, translating technical risk into clear business impact. Deliver security awareness initiatives, phishing simulations and ongoing engagement with suppliers, auditors, MSSPs and SOC partners.
• Continuous Improvement: Identify opportunities to optimise and automate security controls, contribute to the cyber‑security roadmap and maintain awareness of emerging threats, technologies and industry best practice.