Securing the Supply Chain: What the UK Government’s New Cyber Mandates Mean for Your Business

The UK government is introducing new legislation to fortify cyber defenses across its digital ecosystem, including suppliers that serve the public sector. Announced in the July 2024 King’s Speech, the proposed Cyber Security and Resilience Bill aims to modernize existing cyber laws and expand regulatory oversight better to protect national infrastructure and public services from digital threats.

This shift signals a significant rise in cybersecurity expectations—particularly for small and medium-sized enterprises (SMEs) that form the backbone of the UK’s public sector supply chain. The message is clear: cybersecurity is not a “nice-to-have”—it’s a business-critical requirement.

Behind the Push: Rising Supply Chain Attacks

A primary driver of the legislation is the growing threat posed by supply chain-based cyberattacks. Adversaries increasingly target smaller suppliers as entry points into larger government systems. A single breach at an insecure vendor can expose sensitive data, disrupt public services, or even enable ransomware campaigns that lock entire departments out of their systems.

To address this, the proposed Bill empowers UK cyber regulators to:

• Designate certain vendors as “Critical Suppliers” and bring them under direct cybersecurity oversight.
• Enforce mandatory incident reporting, including ransomware disclosures.
• Expand coverage to include managed service providers (MSPs) and cloud providers.

This builds on the UK’s National Cyber Strategy and is informed by recent consultations on supply chain resilience and ransomware readiness.

The Threat Landscape: Why Action Is Urgent

Email-Based Attacks

Phishing and email spoofing remain among the most common tactics to breach public sector systems. Attackers impersonate trusted suppliers to trick staff into clicking malicious links or surrendering credentials.

The scale of the problem is significant: the UK’s National Cyber Security Centre (NCSC) reports that its Suspicious Email Reporting Service (SERS) has received over 41 million reports from the public since its launch in April 2020—underscoring the scale of phishing threats in the UK.

Supply Chain Lateral Movement

Attackers rarely target government systems directly. Instead, they infiltrate by compromising a smaller, less secure vendor and moving laterally through connected systems. This tactic has been observed in multiple international breaches and remains a key concern for UK policymakers.

Ransomware Risks

Ransomware continues to escalate in frequency and severity, often delivered through phishing emails. The government’s updated cyber policy reflects this concern, placing stronger emphasis on resilience, incident response, and breach notification across the entire digital supply chain.

DMARC and Email Authentication: Best Practice, Not Yet Law

One emerging best practice is using Domain-based Message Authentication, Reporting, and Conformance (DMARC) to prevent email impersonation. DMARC ensures only authenticated senders can use a domain, helping to block spoofing attempts.

While DMARC enforcement (e.g., p=reject or p=quarantine) is strongly recommended, it is not currently mandated under the Cyber Security and Resilience Bill as of mid-2025. However, adopting DMARC is a proactive step suppliers can take now. Here’s how enforcement levels compare:

Getting Help: Tools for a Smooth Transition

Transitioning to full DMARC enforcement—especially for SMEs—can be technically challenging. Missteps can disrupt legitimate communications. This is why platforms like PowerDMARC are helping suppliers decode the complexities of DMARC reports (often in XML) and make confident, informed policy decisions.

These solutions offer:

• Clear dashboards convert technical data into human-readable insights
• Tools to identify unauthorized email senders
• Domain checks to assess compliance status
• Guided transitions from monitoring (p=none) to full enforcement (p=reject)

While these services are not mandated, they can be invaluable in raising your cyber hygiene to expected standards. Using a DMARC checker by email authentication providers like PowerDMARC is a smart step toward readiness.

Broader Implications: Raising the UK’s Cybersecurity Floor

Although the legislation primarily affects public sector suppliers, its impact is expected to ripple across the economy. Private-sector organizations will likely adopt similar procurement and risk management requirements as government cybersecurity standards tighten.

This reflects a growing international trend—from the EU’s NIS2 Directive to the US’s CISA guidance—highlighting that cyber resilience is becoming a shared responsibility across sectors.

From Mandate to Competitive Advantage

The UK’s Cyber Security and Resilience Bill is more than a legal obligation—it’s a blueprint for operational resilience in an increasingly risky digital landscape. By acting early, suppliers can not only maintain compliance but also:

• Strengthen client trust
• Reduce breach risk
• Gain a competitive edge in both public and private markets

While some implementation details are still forthcoming, the direction is clear: stronger cybersecurity obligations are on the horizon for UK businesses connected to public services. Preparing now—especially around email security, supply chain risk, and incident response—will position your organisation for compliance and resilience in the years ahead.