The UK’s Critical National Infrastructure (CNI) is facing rising cyber risk from hostile nation-states, organised criminal groups, and now AI-enhanced adversaries. Attacks are becoming more strategic. Threat actors are scaling their operations with alarming efficiency and evading detection more effectively. This poses an escalating threat to the public sector, where a full-scale cyber incident could cost the UK millions, even billions, and have severe consequences for public safety and national stability.
Despite growing awareness of cyberthreats, the public sector continues to lag behind in resilience. Survey findings from the World Economic Forum reveal that nearly 40% of public sector respondents perceive their resilience to be inadequate, compared to only 10% of medium-to large organisations in the private sector. At the same time, risky ‘legacy’ IT systems are estimated to still make up over a quarter of the public sector’s IT estate, according to a UK Parliament Report.
With the threat of a catastrophic cyberattack on the UK’s CNI looming ever larger, the public sector must adopt transformative approaches to stay ahead. Nation-state adversaries are rapidly adopting AI to scale their attacks, and the public sector must fight fire with fire. At the forefront of this shift is agentic AI – autonomous, goal-driven systems capable of proactively detecting, mitigating, and responding to complex cyberthreats in real time.
Essential Services Become Critical Targets
Critical national infrastructure, from healthcare and utilities to manufacturing, remains a prime target for cyberattacks. When attackers successfully breach these sectors, the consequences extend far beyond financial losses. These incidents can disrupt essential services, endanger public safety, and compromise national security. Increasingly, these attacks are driven by nation-state actors seeking to exploit vulnerabilities for strategic, economic, or political gain.
Defending critical industries remains a core challenge that is only becoming more complex as threat tactics evolve. Traditional security tools that depend on manual intervention, static rules, and reactive responses are no longer enough to keep up with AI-powered threat actors who:
- Automate attack campaigns to evade detection – Nation-state actors are leveraging AI to dynamically modify malware, phishing techniques, and intrusion methods in real time, making them harder to detect with traditional, rules-based tools. These AI-powered campaigns can adapt during attack, bypassing signature-based defences and mimicking legitimate user behaviour to remain undetected.
- Exploit zero-day vulnerabilities – Advanced threat actors are increasingly using AI to scan for and exploit unknown or unpatched vulnerabilities at greater speed. By the time security analysts identify and respond to the threat, critical systems may already be compromised and data exfiltrated.
- Spread laterally through networks – Once inside a network, attackers use AI to move laterally, disguising their activity, escalating privileges, and identifying valuable targets while avoiding detection often for weeks or months. This dwell time allows them to map entire systems, disrupt operations, and exfiltrate data without triggering alarms.
At the same time, ever-changing regulatory compliance adds another layer of complexity to the modern threat landscape. Public sector organisations must align with frameworks, including the UK’s Cyber Assessment Framework (CAF) to improve resilience, whilst also managing limited resources and the growing cybersecurity skills gap.
With threat actors already scaling their attacks on public services, the sector must take proactive steps to gain the edge over evolving threats. This is where agentic AI can transform security operations by detecting anomalies early, making autonomous decisions, and accelerating investigations with deeper insights.
Autonomous, Intelligent, and Aligned to National Resilience
Defending the UK’s critical infrastructure from increasingly sophisticated nation-state cyberthreats requires more than just additional tools. It demands smarter, AI-driven solutions. By integrating agentic AI into security operations, public sector organisations can move beyond reactive firefighting with proactive, adaptive resilience.
With agentic AI, critical sectors gain capabilities that transform how threats are detected, managed, and mitigated, delivering faster, smarter, and more adaptive defences that directly strengthen national resilience. This includes:
- Autonomous Threat Detection and Real-Time Response – Agentic AI continuously scans systems for anomalies, correlating data from across endpoints, networks, and applications. When it detects suspicious behaviour, it can respond instantly. This enables the public sector to isolate compromised networks, launch forensic investigations, and initiate containment without waiting for manual input.
- AI-Powered Decision Support – During high-pressure incidents agentic AI can provide deep security insights and scenario modelling to support decision-makers. Whether responding to a breach or planning for future risks, it empowers leaders with data-driven clarity. For the public sector, where services are essential to modern society, this intelligent insight can lead to faster response times, reduced disruption, and more resilient public service delivery.
- Reduced Dwell Time – Agentic AI doesn’t just detect threats. It actively works to minimise their impact. By identifying malicious activity during the early stages, these intelligent agents can shut down attack vectors, revoke compromised credentials, and quarantine affected systems. This dramatically reduces attacker dwell time, which is often the key factor in limiting data loss and service disruption.
- Risk Modelling Aligned with CAF – One of the most powerful aspects of agentic AI is its ability to continuously assess evolving risks in real-time. By aligning with the UK’s CAF, it ensures public sector organisations maintain compliance while adapting to new threats. Agentic AI is capable of adjusting models as infrastructure changes, ensuring risk postures remain accurate and actionable.
Fighting AI with AI
As nation-state actors adopt AI to ramp up their threat tactics, the public sector must respond. To match the speed, sophistication, and persistence of these threats, it must shift its focus on leveraging AI within its own operations to strengthen national cyber resilience.
Strengthening national security in the age of AI requires urgent, coordinated action across the entire public sector. Responsibly embedding agentic AI as part of the UK’s security foundation will be critical to staying ahead of evolving threats and safeguarding the nation’s most vital infrastructure.
