The UK is making its most significant overhaul of cybersecurity regulation in nearly a decade, and operational technology (OT) asset owners are watching closely. Introduced in November 2025, the Cyber Security and Resilience Bill (CSRB) is the biggest change to UK cybersecurity regulations since the Network and Information Systems (NIS) regulations went into effect in 2018. More than just an update to that framework, it fundamentally shifts regulatory expectations to reshape how critical infrastructure operators manage, report and mitigate cyber risk.
Among the biggest changes: under CSRB, almost all OT systems are now firmly in scope as “national resilience” assets.
As the bill wends its way through Parliament, now is the time to understand what’s likely to be required and begin preparing. For example, we know incident reporting is coming. Ahead of specifics, you can determine who should make which decisions and how information should flow.
This article breaks down what the CSRB is, where it stands in the legislative process, and what its key provisions mean for newly in-scope asset owners. We’ll also look at how the National Cyber Security Centre’s (NCSC) Cyber Assessment Framework (CAF) fits into the picture and highlight how Nozomi Networks can help you prepare.
Understanding the CSRB: What It Is and Where It Stands
The CSRB builds on NIS, which introduced the UK’s first clear legal responsibilities for OT asset owners in 2018. It set expectations for cybersecurity preparedness that operators of essential services must meet. Eight years later, technology, geopolitics and the threat landscape have all evolved, and the government is modernizing its approach.
While the bill’s fine points may still evolve, its overall direction is clear: greater accountability, more prescriptive obligations and wider regulatory reach.
Incident Reporting, Enforcement and Oversight
The CSRB introduces new legal requirements meant to strengthen national resilience, expand regulatory scope and establish a more robust — and enforceable — set of expectations. For organizations that are already in scope under NIS, the biggest differences involve mandatory incident reporting and stricter, more enforceable penalties. In essence, the bill equips regulators with the authority and mechanisms needed to police OT cybersecurity more aggressively.
Current Legislative Status
The bill is progressing through Parliament and, as of 18 March, has entered the Report Stage in the House of Commons. With the completion of the Committee Stage — widely regarded as the most dynamic and influential phase of the legislative process — the most intensive period of scrutiny and amendment is now behind the bll.
Key Provisions in the CSRB
While the bill’s fine points may still evolve, its overall direction is clear: greater accountability, more prescriptive obligations and wider regulatory reach. Several core elements are already apparent:
- Expanded scope: Many more OT environments will fall under regulatory oversight, including operators controlling large energy loads, data centers, digital service providers and managed service providers.
- Incident reporting: Similar to EU NIS2, the CSRB introduces mandatory cyber-incident reporting for regulated entities. Specific thresholds and timelines are still forthcoming, but it is expected to force asset owners to report incidents to their regulatory body.
- Stronger penalties and enforcement: Penalties will be significant and, in some cases, stricter than those under NIS2. Critically, the bill introduces language enabling regulators to recoup the costs of their oversight activities directly from regulated operators.
- National resilience focus: Cyber incidents that could cause physical disruption or safety impacts receive elevated attention. Almost all OT systems are now considered assets of national resilience.
NCSC CAF Alignment
The NCSC’s CAF remains the most relevant guide for operational preparedness. Especially for newly in-scope asset owners, it’s an invaluable reference. Several CAF principles are specifically relevant for CSRB compliance.
CAF Objective A: Managing Security Risk
A3.a Asset Management
You must designate a responsible individual for asset management, and your organization must have complete visibility into OT assets across their lifecycle. With long equipment lifespans, legacy technologies and complex interdependencies, OT environments are notoriously difficult to map. But under CSRB expectations, you’ll need a defensible, continuously updated asset inventory that supports risk assessment, vulnerability management and incident response.
CAF Objective B: Protecting Against Cyber Attacks
B4.d Vulnerability Management
Knowing what vulnerabilities exist in your environment and how they affect different assets is essential. OT vulnerabilities are often unique due to vendor diversity, proprietary OT protocols and operational constraints. A well-defined process for identifying, tracking and remediating vulnerabilities is a core component of meeting CSRB requirements.
CAF Objective C: Detecting Cybersecurity Events
C1 Security Monitoring
Monitoring is a central pillar. Organizations must maintain logging, alerts and monitoring functions designed for industrial environments, not just IT. This includes ensuring SOC staff or service partners have OT-specific skills.
C2.a Threat Hunting
A newer CAF requirement, threat hunting becomes a business-as-usualusual activity proportionate to organizational risk. For OT operators, this means proactive, intelligence driven searches for malicious activity across converged IT/OT networks.
How Nozomi Networks Can Help
Navigating regulatory change, especially one as sweeping as the CSRB, can seem overwhelming. Nozomi Networks helps organizations strengthen their OT and IoT security posture in ways directly aligned with CSRB and CAF requirements.
With deployments across energy, manufacturing, transportation building management and critical national infrastructure, we’re already helping UK OT asset owners strengthen resilience and stay ahead of emerging regulatory requirements. For more help clarifying what the CSRB requirements will mean for you, contact us today.
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