The UK is not subject to NIS2 directly post-Brexit. The legal NIS-equivalent regime is the Network and Information Systems Regulations 2018, which applies to a narrower population than NIS2 — Operators of Essential Services (OES) in energy, transport, healthcare, water, and digital infrastructure, plus Relevant Digital Service Providers (RDSPs). The UK government has indicated intent to update those 2018 Regulations to broadly align with — but not identically to — NIS2 standards. The National Cyber Security Centre (NCSC) is the technical authority and CSIRT; the ICO and sector regulators are competent authorities for RDSPs and OES respectively.
For most UK organisations outside the OES/RDSP scope, the practical cybersecurity baseline is Cyber Essentials and Cyber Essentials Plus — NCSC-backed certification schemes (administered by IASME) that cover the five core technical controls: firewalls, secure configuration, user access control, malware protection, and security update management. CE is required for many UK public-sector contracts and is increasingly the answer UK suppliers give when EU buyers ask for evidence of cybersecurity posture under their NIS2 supply-chain assessments. A UK supplier holding current CE Plus certification is a common, defensible — though not framework-equivalent — substitute for the NIS2 Article 21(2)(d) evidence an EU buyer is collecting.
Authoritative source for United Kingdom cybersecurity guidance — including the certification schemes UK suppliers commonly hold when EU NIS2 buyers ask for evidence of posture.