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Security report for sizewellc.com

Sizewell C · Energy · United Kingdom

Low risk. 3 critical or high findings in Security headers, GDPR outside view and 1 other check.

Security score

76/100

Risk levelLow

0–100, higher is better. How it is calculated

Sizewell C is a major British nuclear power project aimed at delivering clean, reliable electricity to approximately 6 million homes while supporting tens of thousands of jobs across the UK. Majority owned by the UK Government, the project emphasizes energy security, environmental stewardship, and community benefits. The website reflects a mature digital presence with comprehensive content targeting local communities, investors, and job seekers. Technically, the site is built on WordPress with modern SEO and analytics tools integrated, ensuring good performance and accessibility. Security posture is strong with HTTPS enforced and consent management implemented, though explicit security headers could be improved. Overall, the site demonstrates high professionalism and trustworthiness, aligned with the project's stature and government backing.

Scanned

NIS2 and GDPR posture

GDPR outside view
68/ 100 · Medium
Checks completed
5of 7

NIS2 Art. 21(2)

  1. (a) Risk analysis and security policies: Not visible from outside
  2. (b) Incident handling: One indicator
  3. (c) Business continuity, backups and crisis management: Not visible from outside
  4. (d) Supply chain security: Not visible from outside
  5. (e) Secure acquisition, development and maintenance, including vulnerability handling: Partly checked
  6. (f) Assessing the effectiveness of security measures: Not visible from outside
  7. (g) Cyber hygiene and security training: Not visible from outside
  8. (h) Cryptography and encryption: Partly checked
  9. (i) HR security, access control and asset management: One indicator
  10. (j) Multi-factor authentication and secured communications: Not visible from outside

This scan rated NIS2 with an earlier keyword method that is no longer shown; rescan for the per-article view. Risk management, continuity, supply chain, training, MFA, management oversight (Art. 20) and incident reporting (Art. 23) need internal evidence, and Guard cannot tell whether NIS2 applies to this organisation.

GDPR is indicative only, based on publicly visible signals: Articles 7, 12, 13 and 32 of Regulation (EU) 2016/679 and Article 5(3) of the ePrivacy Directive. Not a certification or legal assessment.

Priority findings

3 findings rated critical or high. Fix these first.

  1. Security headers

    Security headers are instructions your web server sends to every visitor’s browser. Missing ones leave visitors more exposed to attacks such as clickjacking and injected scripts.

    • High

      Missing Strict-Transport-Security header

      Forces HTTPS connections

      What to do: Add "Strict-Transport-Security: max-age=31536000; includeSubDomains; preload"

      • CWE-319
      • OWASP A04:2025
      • ASVS V3.4.1

  2. GDPR outside view

    These are the privacy signals visitors and data protection authorities look for under GDPR.

    • High

      No Cookie Consent Banner found

      GDPR requires explicit consent for non-essential cookies

      What to do: Implement a cookie consent banner that appears on first visit

  3. SSL/TLS

    TLS encrypts the connection and proves the site is really yours. Weak or expiring certificates trigger browser warnings and put traffic at risk.

    • High

      Weak Protocols Supported

      Server supports weak protocols: TLSv1.1

      What to do: Disable TLS 1.0, TLS 1.1, and all SSL versions

      • CWE-327
      • OWASP A04:2025
      • ASVS V12.1.1

Need hands-on remediation? Email guard@offseq.com

Keep watching sizewellc.com

This scan found 13 issues across 4 checks. Monitoring re-runs those checks daily, emails you when something material changes and records each fix, so you can show progress.

Daily monitoring

Recommended

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  • TLS certificates and expiry
  • DNS records
  • SPF, DKIM and DMARC
  • Security headers
  • GDPR and NIS2 posture
  • Exposed services
  • Third-party trackers
  • Security score drift

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Results by check

Each check with its score, findings and the evidence it collected.

How this score is calculated

The security score runs 0–100, higher is better. It is the plain average of the security checks that completed in this scan, each counted equally. A check that could not run is left out: it counts neither as a pass nor as a fail.

Counted in this score

SSL/TLS
72
Security headers
65
Network security
100
GDPR outside view
68
Average
76

Not counted

  • Email security: did not complete in this scan.
  • DNS health: did not complete in this scan.
  • NIS2 outside view: Re-weights evidence from the TLS, email, DNS, network and hygiene checks, so counting it would count that evidence twice. Shown on its own.
  • OffSeq Observations: An AI reading of the site, useful context but not reproducible evidence. Shown on its own.

Findings that cap the score at 49

Each of these is serious on its own, so while any is present the site cannot rate better than high risk, however good the other checks are.

  • The certificate is not trusted by browsers
  • The website is not served over HTTPS
  • A database, remote desktop, file-sharing or Telnet service is reachable from the internet
  • The page loads a script from a compromised source
  • The domain registration has expired
  • SPF authorises every server to send mail as the domain

Partial scans

When the site blocks Guard or most checks cannot run, the score covers only the checks that ran (usually DNS and email), is capped at 75 and is shown as partial, without a risk level.

Risk levels

  • Critical0–25
  • High26–49
  • Medium50–75
  • Low76–100

Technical appendix

Business context, site observations and technical notes gathered during the scan, and the standards behind each reference.

Business context

Business profile

The business operates in the energy sector, focusing on nuclear power generation with a strong emphasis on sustainability and community impact. Its market position is significant as the first majority British-owned nuclear power station in decades, supported by substantial government investment. The business model includes public-private investment, supply chain engagement, and workforce development through apprenticeships. The website's partnership ecosystem includes supply chain trackers and career platforms, indicating a broad operational footprint. Growth indicators include recent government funding milestones and regulatory approvals. The company maintains transparency through published policies and community engagement, reinforcing its credibility.

Security posture

The website exhibits a mature security posture with HTTPS enforced and a robust cookie consent mechanism that aligns with GDPR requirements. No critical vulnerabilities or exposed sensitive data were detected in the HTML content. However, the absence of explicit security headers such as Content-Security-Policy and X-Frame-Options suggests room for enhancement. Incident response and security policy information are not prominently published, which could be improved to bolster trust and readiness. Overall, the security practices are sound but could benefit from formalized documentation and additional header implementations.

Recommendations

  1. Implement explicit security headers including Content-Security-Policy, X-Frame-Options, and X-Content-Type-Options to enhance protection against common web attacks.
  2. Publish a dedicated security policy and incident response page to improve transparency and preparedness.
  3. Regularly audit and update third-party scripts and plugins to mitigate potential vulnerabilities.
  4. Consider adding a security.txt file to facilitate responsible vulnerability disclosure.
  5. Enhance visibility of data protection officer or privacy contact details to strengthen GDPR compliance signals.

Contact details published on the site

Addresses
Legal name
NNB Generation Company (SZC) Limited
Site observations

Automated reading of the public site. Ratings are indicative.

Business

Company
Sizewell C
Description
Sizewell C is a British nuclear power project providing reliable, low-carbon electricity for around 6 million homes, supporting 70,000 UK jobs and relying on over 2,000 UK-based suppliers.
Key services
Nuclear power generation, Job creation and apprenticeships, Community engagement and benefits, Environmental conservation and net zero technologies
Content quality
excellent
Branding
consistent

Technology

Stack
WordPress, Yoast SEO, Gravity Forms, jQuery, Google Tag Manager, Google Analytics, Fancybox, Paroller.js
Platforms
WordPress
Performance
moderate
Mobile
good
Accessibility
good
SEO
good

Security

Observed score
85/100
Good practices seen
  • HTTPS enforced
  • Use of Google Tag Manager with async loading
  • Consent management for cookies
  • No exposed sensitive data in HTML
  • Secure form handling via Gravity Forms

Analytics and tracking

Services
Google Analytics
Tracking level
moderate
Privacy practices
good

Advertising

Ad networks
DoubleClick by Google
Transparency
good

Site quality

Design
excellent
User experience
excellent
Content relevance
excellent
Navigation
excellent
Professionalism
excellent
Trustworthiness
high

Key observations

  1. Website is professionally designed and well maintained.
  2. Strong focus on community engagement and environmental responsibility.
  3. Comprehensive cookie consent mechanism implemented.
  4. Multiple government and regulatory references enhance trust.
  5. No critical security issues detected in the HTML content.
  6. Use of modern web technologies and SEO best practices.
Technical notes

Notes

The website is powered by WordPress CMS with integration of Yoast SEO for search optimization and Gravity Forms for data collection. It uses jQuery and several JavaScript libraries for UI enhancements such as carousels and video handling. Google Tag Manager and Google Analytics are employed for tracking and analytics. The site demonstrates good mobile responsiveness and accessibility features. Performance is moderate, with potential improvements in script loading and caching. The technical infrastructure supports a professional and user-friendly experience but could benefit from further optimization and security hardening.
Standards and sources

Reference chips under each finding point to the standard, regulation or specification the finding relates to. They are taken from the official datasets below and mapped conservatively: a finding with no defensible link shows none. NIS2 and GDPR references mark where a finding is relevant evidence, not a compliance verdict. Implementing Regulation (EU) 2024/2690 binds digital infrastructure and digital service providers; for other entities it is the most detailed public reading of the Article 21 measures. WCAG, EN 301 549, European Accessibility Act and Web Accessibility Directive references name the requirement an automated accessibility rule relates to; they are not a conformance verdict.

Retrieved 2026-10-25

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