The Biggest Data Breaches of 2025: What UK Businesses Need to Learn for 2026
If 2025 proved anything, it’s that cyber criminals aren’t slowing down. From high-profile retail breaches to enormous credential dumps quietly circulating online, UK organisations have felt the impact of a fast-evolving threat landscape. While big names grabbed the headlines, the lessons apply just as much to small businesses, charities and local organisations.
Below is a look at some of the most significant breaches of the year, what they mean for organisations in the UK, and why 2026 needs to be the year where businesses take a more proactive and connected approach to cybersecurity and data protection.
UK retail and consumer brands under pressure
One of the biggest incidents of the year came from a cyberattack affecting several major UK retail brands including Marks & Spencer, Co-op and Harrods. The attackers gained access through a third-party supplier and exposed millions of customer records, including names, email addresses and home addresses. The incident caused major disruption to online retail systems and served as a reminder of how dependent modern businesses are on suppliers. When a partner is compromised, you can be too.
The rise of the mega credential dump
June 2025 saw the publication of a staggering collection of stolen credentials – more than 16 billion records. This wasn’t a single breach, but an aggregation of information stolen through malware, older breaches and unsecured databases. For UK businesses, the risk is simple and serious: employees often reuse passwords. A credential leak of this scale dramatically increases the likelihood of account compromise, particularly for organisations with weak password policies or no multifactor authentication in place.
Third-party and supply-chain breaches still dominate
A common theme across 2025 was that attackers rarely walked through the front door. Instead, they targeted third-party software providers, outsourced service partners and suppliers, knowing that many organisations continue to underestimate this risk. For businesses that rely heavily on external partners, this trend should act as a prompt to review contracts, ask tougher security questions and ensure suppliers meet the same standards you hold internally.
The role of AI in both reducing and increasing breach costs
The annual IBM Cost of a Data Breach Report highlighted two contrasting realities for UK organisations. Those using AI and automation within their security operations saw breach-related costs fall significantly. However, organisations without AI governance struggled, and some were exposed to additional risk from unapproved or poorly managed AI tools. The message here is clear: AI can help, but only when introduced with proper oversight and policies.
What 2025 tells us about the year ahead
When you step back and look at the bigger picture, several lessons stand out.
First, not all breaches are dramatic headlines. Some of the most damaging incidents come from quiet, unnoticed credential leaks or small vulnerabilities in legacy systems.
Second, every organisation is part of a bigger digital ecosystem. Even if your internal systems are strong, you remain exposed if your partners are not.
Third, technology alone will not protect a business. AI and automation show real promise, but they must be supported by strong governance, staff training and clear processes.
And finally, customer trust is more fragile than ever. Once data is exposed, rebuilding confidence takes far longer than responding to the breach itself.
How Cybata can help protect your business in 2026
Cybata’s approach combines data protection, cybersecurity and compliance in a way that reflects how modern organisations actually operate. The two disciplines are closely linked, and the most resilient businesses treat them as such.
We help organisations understand the data they hold, where it lives, and who has access to it. This creates a foundation for stronger decision-making and faster response in the event of an incident.
Our cybersecurity assessments and penetration tests identify vulnerabilities before attackers can exploit them, including risks coming from suppliers and third-party services.
We also work with organisations to build practical incident response plans that cover both the technical and legal requirements of a modern data breach. Knowing who to notify, how to contain an incident and what to communicate can make all the difference.
And because people remain one of the most common attack vectors, we place real emphasis on training. When staff understand the risks, they’re better equipped to recognise suspicious activity and act quickly. This is also why we’ve developed in both physical and digital versions, the ‘What Would You Do? (Data & Cyber) game.
Together, these elements help build genuine resilience, not just compliance. In a year where the threat landscape is only set to grow more complex, businesses that take a joined-up approach will be far better placed to protect their data, operations and reputation.
If you would like support reviewing your data protection processes, strengthening your cybersecurity or preparing for the challenges of 2026, Cybata is here to help.
