The Challenge

As Lead Consultant engaged by Sizewell C Nuclear, I facilitated a comprehensive IT Health Check (ITHC) to provide objective, external validation of the project's overall cybersecurity direction. Operating within the highly regulated Critical National Infrastructure (CNI) sector, the primary challenge was to deliver absolute assurance to the executive board and critical project investors that the cybersecurity posture was robust and tracking against its strategic goals — without disrupting live operations in a large-scale nuclear infrastructure environment.

Driving investor confidence and executive trust required external, third-party validation of the project's cybersecurity trajectory at a critical funding juncture.
I navigated the strict architectural security constraints of a large-scale nuclear infrastructure environment, where standard assessment methodologies required careful adaptation.
I delivered a transparent assessment of the security function's maturity while managing expectations across senior board and investor stakeholders.
I ensured all activities aligned strictly with NCSC CHECK guidance and CREST standards — non-negotiable within a UK Government CNI context.

The Approach

To deliver a regulator-grade assessment, I partnered with external CREST-accredited security specialists, PTP, to execute a rigorous, intelligence-led evaluation. I led and coordinated the engagement end-to-end, structuring the activities across a risk-based technical assurance methodology that seamlessly combined vulnerability assessments, deep-dive configuration reviews, and controlled penetration testing. I ensured all activities were strictly aligned to National Cyber Security Centre (NCSC) CHECK guidance and CREST standards throughout, alongside established frameworks including NIST CSF and ISO 27001. I maintained close coordination between PTP's external testing team and Sizewell C's internal security function at every stage, ensuring thorough coverage, zero operational disruption, and a findings report that met all compliance and investor reporting mandates.

The Results

The engagement concluded with Sizewell C scoring above the industry average when benchmarked against peer organisations, independently validating the effectiveness of the current cybersecurity strategy and providing the executive board with the evidence required to maintain stakeholder and investor confidence.

Business & Security Impact

Regulator-Grade Assurance: Delivered independent validation to the executive board and investors, meeting critical reporting mandates at a key funding milestone.
Measurable ROI: Provided proactive vulnerability identification—a practice industry data shows offers up to a 10:1 return on investment by avoiding the UK average £195k cost of a major cyber incident.
Financial Optimisation: Established high-assurance testing evidence that positions the organization to negotiate 5–15% reductions in cyber insurance premiums.
Accelerated Remediation: Produced a risk-weighted remediation roadmap that drastically reduces internal Mean Time To Remediate (MTTR) by providing prioritized, expert-led actions.
Strict Compliance: Demonstrated unbroken alignment with NCSC CHECK, CREST, NIST CSF, and ISO 27001 standards throughout the assessment lifecycle.
Above-Average Maturity: Successfully benchmarked the organization's cybersecurity posture above the industry average, cementing the confidence of regulators and supply chain partners.

My established working relationship with Sizewell C, built through prior engagements on the same programme, meant I understood the project's security architecture and stakeholder landscape before the assessment began — enabling me to scope the ITHC accurately, brief external testers efficiently, and translate findings into board-level language with no ramp-up time.