Top Cybersecurity Companies in the UK
Cybersecurity is a critical and rapidly growing sector in the UK, driven by increasing digital threats and regulatory requirements. Here are the top cybersecurity companies in the UK for 2026, ranked by number of employees.
| # | Company | Location | Employees | Revenue |
|---|---|---|---|---|
| 1 | KASPERSKY LABS LIMITED | London | 4,670 | £622.0M |
| Global cybersecurity company providing endpoint protection, threat intelligence, and security solutions for consumers and enterprises. Kaspersky's research lab is one of the world's leading sources of cyber threat analysis. | ||||
| 2 | SOPHOS GROUP LIMITED | Abingdon | 4,500 | £850.0M |
| Next-generation cybersecurity company providing endpoint protection, firewall, email security, and managed threat response solutions. Sophos protects over 600,000 organisations and 100 million users worldwide. | ||||
| 3 | DARKTRACE LIMITED | Cambridge | 2,411 | £549.2M |
| AI-powered cybersecurity company using self-learning technology to detect and autonomously respond to novel cyber threats in real time. Darktrace's Enterprise Immune System protects thousands of organisations globally. | ||||
| 4 | NCC GROUP PLC | Manchester | 2,300 | £350.0M |
| Global cybersecurity and risk mitigation specialist providing penetration testing, security consulting, managed detection and response, and software escrow services. Listed on the London Stock Exchange. | ||||
| 5 | MCAFEE SECURITY UK LTD | London | 1,301 | £634.1M |
| Consumer and enterprise cybersecurity company providing antivirus, identity protection, and privacy solutions. McAfee protects millions of users worldwide from malware, phishing, and online threats. | ||||
| 6 | GB GROUP PLC | Chester | 1,132 | £282.7M |
| Identity verification and fraud prevention platform helping businesses verify customer identities, prevent fraud, and manage regulatory compliance. GBG processes billions of identity checks annually across 70+ countries. | ||||
| 7 | SNYK LIMITED | London | 1,086 | £222.3M |
| Developer-first security platform helping software teams find and fix vulnerabilities in code, open source dependencies, containers, and cloud infrastructure. Snyk integrates directly into CI/CD workflows. | ||||
| 8 | CROWDSTRIKE UK LIMITED | London | 753 | £163.0M |
| Cloud-native endpoint protection platform using AI-powered threat detection and response. CrowdStrike's Falcon platform provides real-time visibility and protection across enterprise endpoints worldwide. | ||||
| 9 | BYTES SOFTWARE SERVICES LIMITED | Leatherhead | 696 | £1.2B |
| IT solutions provider specialising in cybersecurity software licensing, cloud services, and managed security. Listed on the LSE, Bytes helps organisations procure and deploy security solutions from leading vendors. | ||||
| 10 | LEXISNEXIS RISK SOLUTIONS UK LIMITED | Cardiff | 676 | £90.6M |
| Data analytics and risk management company providing fraud prevention, identity verification, and compliance solutions for financial services, insurance, and government organisations. | ||||
| 11 | MIMECAST SERVICES LIMITED | London | 631 | £247.1M |
| Cloud-based email security and management platform providing protection against phishing, ransomware, and impersonation attacks. Mimecast also offers email archiving, continuity, and security awareness training. | ||||
| 12 | RAPID7 INTERNATIONAL LIMITED | London | 630 | £216.2M |
| Cybersecurity analytics and automation company providing vulnerability management, incident detection and response, and cloud security. Rapid7's Insight platform helps security teams detect and respond to threats. | ||||
| 13 | SOPHOS LIMITED | Abingdon | 622 | £662.1M |
| Operating entity of Sophos providing endpoint, network, email, and cloud security products. Sophos Central offers a unified management console for deploying and managing security across enterprise environments. | ||||
| 14 | CLARANET LIMITED | London | 534 | £102.1M |
| Managed IT services and cybersecurity provider offering cloud hosting, network security, compliance, and managed detection and response services for mid-market and enterprise organisations. | ||||
| 15 | PROOFPOINT LIMITED | Bury St. Edmunds | 520 | £91.3M |
| Enterprise cybersecurity company focused on protecting people from advanced threats via email, cloud, and social media. Proofpoint's human-centric approach addresses phishing, business email compromise, and data loss. | ||||
| 16 | PALO ALTO NETWORKS (UK) LIMITED | London | 459 | £1.1B |
| Global cybersecurity leader providing next-generation firewalls, cloud security, endpoint protection, and AI-driven security operations. Palo Alto's Cortex platform uses AI to detect and respond to sophisticated threats. | ||||
| 17 | KNOWBE4 UK, LTD. | Leeds | 429 | £24.3M |
| Security awareness training and simulated phishing platform helping organisations build a security-first culture. KnowBe4 is the world's largest provider of security awareness training. | ||||
| 18 | FORTRA INTERNATIONAL GROUP LIMITED | Altrincham | 426 | £71.0M |
| Cybersecurity and automation software company providing data security, infrastructure protection, and managed security services. Fortra helps organisations reduce risk and simplify their security operations. | ||||
| 19 | F5 NETWORKS LIMITED | Chertsey | 405 | £546.6M |
| Application security and delivery company providing web application firewalls, bot protection, DDoS mitigation, and API security. F5 protects the world's largest enterprises and service providers. | ||||
| 20 | TANIUM UK LIMITED | Reading | 370 | £119.4M |
| Endpoint management and security platform providing real-time visibility and control over every endpoint across enterprise networks. Tanium enables IT teams to manage, secure, and remediate endpoints at scale. | ||||
| 21 | OKTA UK LTD | London | 342 | £83.8M |
| Identity and access management platform providing single sign-on, multi-factor authentication, and lifecycle management. Okta helps organisations securely manage user access to applications and data. | ||||
| 22 | S-RM INTELLIGENCE AND RISK CONSULTING LIMITED | London | 339 | £57.5M |
| Corporate intelligence and cybersecurity consultancy providing incident response, threat intelligence, and cyber risk advisory services. S-RM helps organisations prepare for and respond to cyber attacks. | ||||
| 23 | ZSCALER UK LTD. | London | 325 | £96.9M |
| Cloud security company providing zero trust network access, secure web gateway, and cloud firewall services. Zscaler's cloud-native platform secures internet traffic for enterprises without traditional hardware. | ||||
| 24 | IDEMIA UK LIMITED | Tewkesbury | 304 | £70.6M |
| Identity security company providing biometric solutions, secure document authentication, and digital identity services for governments, enterprises, and financial institutions worldwide. | ||||
| 25 | IMMERSIVE LABS LTD | Bristol | 303 | £42.6M |
| Cybersecurity workforce resilience platform that continuously measures and improves human cyber capabilities through hands-on labs, simulations, and crisis exercises for enterprise security teams. | ||||
| 26 | TEXECOM LIMITED | Rossendale | 296 | £37.2M |
| Intrusion detection and security alarm manufacturer providing wired and wireless security systems for residential, commercial, and industrial premises. Texecom exports to over 60 countries worldwide. | ||||
| 27 | NETSPARKER HOLDINGS LIMITED | London | 283 | £63.3M |
| Web application security testing company (now Invicti) providing automated vulnerability scanning and dynamic application security testing (DAST) tools for enterprises and security teams. | ||||
| 28 | EXCLUSIVE NETWORKS LIMITED | Alton | 282 | £611.9M |
| Specialist cybersecurity distributor connecting vendors with channel partners and enterprise customers. Exclusive Networks provides value-added distribution for leading security technology vendors across Europe. | ||||
| 29 | EGRESS SOFTWARE TECHNOLOGIES LIMITED | London | 276 | £34.0M |
| Email security company providing intelligent data loss prevention, phishing protection, and secure email collaboration. Now part of Proofpoint, Egress uses AI to detect and prevent outbound email threats. | ||||
| 30 | AVECTO LTD | Manchester | 275 | £38.9M |
| Endpoint privilege management company (now BeyondTrust) providing solutions that remove admin rights from endpoints while maintaining user productivity. Avecto pioneered privilege management technology. | ||||
| 31 | BRIDEWELL GROUP HOLDINGS LIMITED | Reading | 268 | £38.6M |
| UK-based cybersecurity services provider offering managed detection and response, penetration testing, and security consultancy. Bridewell specialises in protecting critical national infrastructure and regulated industries. | ||||
| 32 | KOCHO GROUP LIMITED | Cardiff | 257 | £25.1M |
| Managed cybersecurity and identity services provider offering security operations centre services, identity management, and cloud security. Kocho is a Microsoft Solutions Partner for Security. | ||||
| 33 | WITHSECURE LIMITED | London | 255 | £24.3M |
| Enterprise cybersecurity company (formerly F-Secure Business) providing cloud-native security solutions including endpoint protection, vulnerability management, and co-security services. | ||||
| 34 | NOMINET UK | Oxford | 254 | £55.9M |
| UK domain name registry and cybersecurity company. Beyond managing the .UK namespace, Nominet provides Protective DNS services used by the UK government and enterprises to block malicious domains. | ||||
| 35 | QUORUM CYBER SECURITY LIMITED | Edinburgh | 238 | £22.1M |
| Scottish cybersecurity services company providing managed detection and response, incident response, and security consultancy. Quorum Cyber is a Microsoft Intelligent Security Association member. | ||||
| 36 | TESSIAN LIMITED | London | 250 | £30.0M |
| AI-powered email security company using machine learning to prevent data loss, phishing attacks, and human error in enterprise email. Acquired by Proofpoint to enhance their human-centric security approach. | ||||
| 37 | CALLSIGN LTD. | London | 200 | £30.0M |
| AI-powered digital identity and authentication platform using behavioural biometrics and machine learning to verify users. Callsign helps banks and enterprises replace passwords with intelligent authentication. | ||||
| 38 | PRIVITAR LIMITED | London | 150 | £20.0M |
| Data privacy and protection platform enabling organisations to safely use, share, and derive value from sensitive data. Privitar provides data de-identification, masking, and privacy engineering tools. | ||||
| 39 | NETCRAFT LTD | Bath | 200 | £25.0M |
| Internet security services company providing cybercrime detection, takedown services, and anti-phishing solutions. Netcraft's internet monitoring surveys have tracked the growth of the web since 1995. | ||||
| 40 | CADO SECURITY LTD | London | 100 | £15.0M |
| Cloud forensics and incident response platform that automates the collection, processing, and analysis of forensic data across cloud, container, and serverless environments for security teams. | ||||
| 41 | CLEARBANK LIMITED | London | 700 | £190.0M |
| Purpose-built clearing bank with advanced security infrastructure providing real-time payment processing and embedded banking services. ClearBank operates one of the most secure banking platforms in the UK. | ||||
| 42 | GENETEC UK LIMITED | London | 333 | £51.5M |
| Physical security platform providing unified video surveillance, access control, and licence plate recognition solutions. Genetec's Security Center platform protects critical infrastructure and enterprise environments. | ||||
| 43 | SECURITAS TECHNOLOGY LIMITED | Milton Keynes | 377 | £38.8M |
| Security technology company providing electronic security systems, video surveillance, access control, and fire detection solutions for commercial and enterprise premises across the UK. | ||||
| 44 | ACORA LIMITED | Burgess Hill | 438 | £79.1M |
| Managed IT and cybersecurity services provider offering security operations, managed detection and response, and IT infrastructure services for mid-market businesses across the UK. | ||||
| 45 | FSP CONSULTING SERVICES LIMITED | Reading | 272 | £37.5M |
| Cybersecurity and IT consultancy providing managed security operations, threat detection, and digital transformation services. FSP specialises in Microsoft security solutions for enterprise clients. | ||||
| 46 | ZENZERO SOLUTIONS LIMITED | London | 228 | £31.7M |
| Managed IT and cybersecurity services provider offering security monitoring, endpoint protection, and cloud security solutions for small and medium-sized businesses across the UK. | ||||
| 47 | OBRELA HOLDCO LIMITED | London | 255 | £18.9M |
| Managed detection and response cybersecurity company providing 24/7 security operations centre services, threat intelligence, and risk management for enterprises and critical infrastructure. | ||||
| 48 | EXCIS COMPLIANCE LIMITED | London | 677 | £27.8M |
| IT compliance and cybersecurity services company providing managed security, compliance monitoring, and network security solutions for global enterprises and multi-site organisations. | ||||
| 49 | VENN NEWCO LIMITED | London | 245 | £138.0M |
| Technology group providing cybersecurity, IT managed services, and digital workplace solutions. Venn combines multiple specialist security and IT service providers under one platform. | ||||
| 50 | FORTRA INTERNATIONAL LIMITED | Altrincham | 289 | £53.4M |
| Operating entity of Fortra providing data protection, email security, and security automation solutions. Fortra's portfolio includes products for file integrity monitoring, secure file transfer, and threat protection. | ||||
The UK cybersecurity sector has grown significantly in recent years as businesses and government organisations face an ever-increasing volume of cyber threats. The National Cyber Security Centre, part of GCHQ, plays a central role in the UK's cyber defence strategy and works closely with the private sector to improve resilience across the economy.
UK cybersecurity companies offer a wide range of products and services including threat detection and response, identity and access management, encryption, penetration testing, and security consulting. The sector serves customers across all industries, with particularly strong demand from financial services, healthcare, and critical national infrastructure.
Cheltenham, home to GCHQ, has developed a notable cybersecurity cluster, but London remains the largest centre for cybersecurity companies in the UK. Other significant clusters exist in Manchester, Edinburgh, and Belfast, supported by local universities with strong computer science programmes.
This ranking lists the largest UK cybersecurity companies by employee headcount. Each entry links to a detailed company profile with financial information, director data, and filing history drawn from Companies House records.
Frequently Asked Questions
What types of cybersecurity companies are included?
The list covers the full spectrum of cybersecurity businesses, including companies focused on network security, endpoint protection, cloud security, identity management, threat intelligence, and security consulting services.
Why is the UK cybersecurity sector growing?
Growth is being driven by several factors including the increasing frequency and sophistication of cyber attacks, stricter data protection regulations such as GDPR, the shift to remote and hybrid working, and growing awareness of cyber risk at board level in organisations of all sizes.
How are employee counts determined?
Employee counts are sourced from Companies House filings and other public records. Figures represent the most recently reported data available for each company.
Can I compare financial data between these companies?
Yes. Each company profile on CompanyTrack includes financial data from their filed accounts, allowing you to compare revenue, profit, assets, and other metrics where available.