Company lists · Data refreshed September 2026
Top 25 Cybersecurity firms based in the United Kingdom
RevenueBase identified 2,100 cybersecurity firms headquartered in the United Kingdom as of September 2026 and tracks 40,405 professional contacts across them, including 16,845 with verified work emails and 5,377 with mobile numbers. London is the largest hub.
This list covers cybersecurity firms headquartered in the United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 1, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest cybersecurity firms based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 4,963 contacts → | ||||
Strong evidence “Sophos is a cybersecurity leader defending organizations globally with an AI-driven platform and expert-led services.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 2 | 3,059 contacts → | ||||
Indirect evidence “SailPoint equips the modern enterprise to seamlessly manage and secure access to applications and data through the lens of identity – at speed and scale.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 3 | 2,590 contacts → | ||||
Strong evidence “Darktrace is a global leader in AI cybersecurity, providing the essential cybersecurity platform to secure organizations today and for an ever-changing future.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 4 | 1,946 contacts → | ||||
Strong evidence “Hack The Box is the leading AI-powered cybersecurity readiness and upskilling platform, trusted by 1,500+ organizations worldwide, including Fortune 500 enterprises, government…” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 5 | 894 contacts → | ||||
Indirect evidence “ZeroFox is the solution to discover, validate, and disrupt external cyber threats before they harm revenue or reputation.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 6 | 739 contacts → | ||||
Strong evidence “SISA is a global forensics-driven cybersecurity solutions company, trusted by leading organizations for securing their businesses with robust preventive, detective, and corrective…” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 7 | 729 contacts → | ||||
Indirect evidence “Claroty has redefined cyber-physical systems (CPS) protection with an unrivaled industry-centric platform built to secure mission-critical infrastructure.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 8 | 684 contacts → | ||||
Indirect evidence “At Roke, we stand at the forefront of defence and security, delivering cutting-edge intelligence and engineering solutions that protect nations, troops, borders, and businesses.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 9 | 635 contacts → | ||||
Indirect evidence “Everfox delivers trusted connectivity to protect the world's most critical environments, safeguarding the sensitive information behind decision advantage.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 10 | 633 contacts → | ||||
Indirect evidence “MASS, part of the Cohort plc group, helps you realise the value of your data.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 11 | 614 contacts → | ||||
Strong evidence “WithSecure™ is Europe's cybersecurity partner of choice.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 12 | 546 contacts → | ||||
Strong evidence “Yubico (Nasdaq Stockholm: YUBICO) is a modern cybersecurity company on a mission to make the digital world safer for everyone.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 13 | 429 contacts → | ||||
Indirect evidence “BioCatch prevents financial crime by recognizing patterns in human behavior.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 14 | 341 contacts → | ||||
Indirect evidence “Integrity360 is a leading independent cyber security and PCI specialist operating across EMEA and North America, with offices spanning the UK and Ireland, Bulgaria, Italy, Sweden…” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 15 | 304 contacts → | ||||
Indirect evidence “Bridewell is the trusted cyber security partner for organisations operating within Critical National Infrastructure (CNI), as well as companies who want the highest standard of…” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 16 | 292 contacts → | ||||
Indirect evidence “At Quorum Cyber, we're on a mission to help good people win.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 17 | 207 contacts → | ||||
Indirect evidence “At VIPRE Security, our mission is to help humanity prosper by creating a high level of trust that enables digital safety for all.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 18 | 206 contacts → | ||||
Indirect evidence “Netcraft provides powerful phishing detection, cybercrime disruption and website takedown solutions to the world's largest organizations” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 19 | 201 contacts → | ||||
Strong evidence “The Redesign Group is a global technology and cybersecurity consulting firm leveraging design thinking, interdependent subject matter expertise, and emerging technology solutions…” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 20 | 188 contacts → | ||||
Indirect evidence “Intragen is a cyber security business focused on managed Identity solutions and services.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 21 | 168 contacts → | ||||
Strong evidence “Exclusive Networks is a global trusted cybersecurity specialist for digital infrastructure helping to drive the transition to a totally trusted digital future for all people and…” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 22 | 142 contacts → | ||||
Indirect evidence “Logiq is a UK-based cyber security consultancy and secure managed services provider supporting defence, government, and critical national infrastructure (CNI) organisations where…” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 23 | 141 contacts → | ||||
Indirect evidence “CyberSec Consulting, headquartered in the UAE and serving the iMETA market, is a distinguished professional Cyber Security and Consulting services company.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 24 | 135 contacts → | ||||
Strong evidence “At Cipher, we're redefining digital security as the premier cybersecurity leader in the Middle East.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
| 25 | 123 contacts → | ||||
Strong evidence “Our mission is to eliminate the most complex cybersecurity challenge every organization faces: insider risk.” Source: RevenueBase Database · checked Sep 1, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: cybersecurity firms. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.
- Strong evidence
- The company's own public description of its business names cybersecurity firms.
- Partial evidence
- Its own public description names part of cybersecurity firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name cybersecurity firms. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.
RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.
Showing 25 of 2,100 cybersecurity firms based in the United Kingdom
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Cybersecurity firms based in the United Kingdom at a glance
As of Sep 1, 2026Companies by employee count
How this list was built
Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among cybersecurity firms, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.
- Source
- The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
- What qualifies
- Companies headquartered in the United Kingdom whose own description of what they do matches “cybersecurity firms”. Matching reads each company's description, not its industry code or its name.
- RevenueBase Smart Search
- RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names cybersecurity firms), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
- What we exclude
- Companies whose own description does not clearly place them among cybersecurity firms, and records with no verified work email. Companies headquartered outside United Kingdom are excluded even when they keep an office there.
- Match quality
- In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
- Ranking
- Team size, largest first: companies are ordered by the number of professionals RevenueBase tracks at each one. Employee ranges shown are reported bands, for context.
- Verification
- Every listed company carries at least one verified work email, 16,845 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
- Refresh
- This page's figures were pulled from the company graph on September 1, 2026. Lists refresh periodically as the graph is re-checked.
- Corrections
- Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.
Cybersecurity firms by metro
Frequently asked
What is RevenueBase Smart Search?
RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names cybersecurity firms, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.
How many cybersecurity firms are there based in the United Kingdom?
RevenueBase identified 2,100 cybersecurity firms headquartered in the United Kingdom as of September 2026, matched on each company's own description of what it does rather than its industry code.
What is the largest company on this list?
Sophos, headquartered in Abingdon, tops this list with the largest team on record.
Which city has the most cybersecurity firms?
London leads with 891 headquartered companies, followed by Manchester (74) and Birmingham (36).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 16,845 verified decision-maker contacts tracked across these 2,100 companies.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 1, 2026.
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About this data
RevenueBase is a B2B data infrastructure company. Its company graph covers 60 million companies and 398.9 million professional contacts, with emails verified on a rolling cadence rather than scraped once and left to decay. These company lists are generated directly from that graph with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.