Company lists · Data refreshed September 2026

Top 25 AI security firms based in the United Kingdom

Name: AI security firms based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 261 companies tracked

RevenueBase identified 261 AI security firms headquartered in the United Kingdom as of September 2026 and tracks 12,863 professional contacts across them, including 6,840 with verified work emails. London is the largest hub.

This list covers AI security 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 21, 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 21, 2026 86% judged on-target in blind review

261Companies

12,863Contacts tracked

6,840Verified emails

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The 25 largest AI security firms based in the United Kingdom

Ranked by team size

Top 25 of 261 AI security firms based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to AI security firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Sophos	Partial evidence	Abingdon, United KingdomHQ checked Sep 21, 2026	5,001-10,000	4,925 contacts →
	Partial evidence “Sophos is a cybersecurity leader defending organizations globally with an AI-driven platform and expert-led services.” Source: RevenueBase Database · checked Sep 21, 2026
2	Darktrace	Partial evidence	Cambridge, United KingdomHQ checked Sep 21, 2026	1,001-5,000	2,355 contacts →
	Partial 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 21, 2026
3	Mimecast	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	2,304 contacts →
	Indirect evidence “organizations.” Source: RevenueBase Database · checked Sep 21, 2026
4	Securityhq	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	501-1,000	502 contacts →
	Partial evidence “SecurityHQ, a global cybersecurity company pioneering Security Performance Engineering for stronger operational performance and resilience.” Source: RevenueBase Database · checked Sep 21, 2026
5	Quorum Cyber	Indirect evidence	Edinburgh, United KingdomHQ checked Sep 21, 2026	201-500	297 contacts →
	Indirect evidence “At Quorum Cyber, we're on a mission to help good people win.” Source: RevenueBase Database · checked Sep 21, 2026
6	Gorilla Technology Group	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	187 contacts →
	Partial evidence “Headquartered in London U.K, Gorilla is a global solution provider in Security Intelligence, Network Intelligence, Business Intelligence and IoT technology.” Source: RevenueBase Database · checked Sep 21, 2026
7	RED Sift	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	109 contacts →
	Indirect evidence “Red Sift enables organizations to anticipate, respond to, and recover from cyber attacks while continuing to operate effectively.” Source: RevenueBase Database · checked Sep 21, 2026
8	H&m Security Services Limited	Indirect evidence	Woodford Green, United KingdomHQ checked Sep 21, 2026	51-200	78 contacts →
	Indirect evidence “We are an SIA Approved Contractor, specializing in Manned Guarding and CCTV solutions.” Source: RevenueBase Database · checked Sep 21, 2026
9	OSL Technology	Partial evidence	Reading, United KingdomHQ checked Sep 21, 2026	51-200	77 contacts →
	Partial evidence “At OSL, our mission is to deliver adaptive security solutions that protect high-value, risk-prone areas by integrating innovative technologies designed to manage both aerial and…” Source: RevenueBase Database · checked Sep 21, 2026
10	Smartnumbers	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	68 contacts →
	Indirect evidence “We help companies in the fight against fraud.” Source: RevenueBase Database · checked Sep 21, 2026
11	Telesoft	Indirect evidence	Blandford, United KingdomHQ checked Sep 21, 2026	51-200	68 contacts →
	Indirect evidence “The organisations that run our world face relentless complexity and evolving threats.” Source: RevenueBase Database · checked Sep 21, 2026
12	Eset UK	Indirect evidence	Bournemouth, United KingdomHQ checked Sep 21, 2026	51-200	66 contacts →
	Indirect evidence “We help businesses and individuals stay protected in an increasingly complex digital world.” Source: RevenueBase Database · checked Sep 21, 2026
13	Threatspike	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	61 contacts →
	Strong evidence “ThreatSpike is the world's first AI-managed IT and security platform, replacing the legacy MSP model entirely.” Source: RevenueBase Database · checked Sep 21, 2026
14	Senseon	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	54 contacts →
	Indirect evidence “SenseOn deploys alongside all of your existing tools, unifying them into a single investigation plane and augmenting your team with cross-domain correlation, analytics, and…” Source: RevenueBase Database · checked Sep 21, 2026
15	Adarma Security	Indirect evidence	Edinburgh, United KingdomHQ checked Sep 21, 2026	201-500	51 contacts →
	Indirect evidence “We are Adarma, independent leaders in detection and response services.” Source: RevenueBase Database · checked Sep 21, 2026
16	Cyberq Group	Indirect evidence	Birmingham, United KingdomHQ checked Sep 21, 2026	51-200	42 contacts →
	Indirect evidence “CyberQ Group is an award-winning, venture-backed, and globally accredited [ISO27K and CREST] cybersecurity leader dedicated to bridging the "protection gap" for high-stakes…” Source: RevenueBase Database · checked Sep 21, 2026
17	Cybaverse	Strong evidence	Portsmouth, United KingdomHQ checked Sep 21, 2026	51-200	41 contacts →
	Strong evidence “We are on a mission to simplify and scale cyber security by combining AI, automation, expert-led services, in a unified platform: giving every organisation, from MSPs to global…” Source: RevenueBase Database · checked Sep 21, 2026
18	Gratte Brothers Security Systems & Software	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	39 contacts →
	Partial evidence “Gratte Brothers is an experienced provider of integrated security solutions, which are Built on Strong Values and ultimately deliver a measurable return on investment.” Source: RevenueBase Database · checked Sep 21, 2026
19	Supreme Guarding Services	Partial evidence	Rainham, United KingdomHQ checked Sep 21, 2026	201-500	38 contacts →
	Partial evidence “Supreme Guarding Services are an S.I.A Approved contractor which specialises in the provision of manned guarding and security solutions to businesses, Facilities Management…” Source: RevenueBase Database · checked Sep 21, 2026
20	Nothreat	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	36 contacts →
	Partial evidence “The future of IoT/OT security is here.” Source: RevenueBase Database · checked Sep 21, 2026
21	defense.com	Partial evidence	Stevenage, United KingdomHQ checked Sep 21, 2026	51-200	32 contacts →
	Partial evidence “Defense.com is transforming the way businesses manage cyber security by allowing them to easily identify, prioritise and remediate threats.” Source: RevenueBase Database · checked Sep 21, 2026
22	Intrinsic Security	Partial evidence	Peterborough, United KingdomHQ checked Sep 21, 2026	51-200	32 contacts →
	Partial evidence “Intrinsic Security is a UK-headquartered cybersecurity firm delivering 24/7 threat detection, incident response, and resilience across cloud, hybrid, OT, IoT, and identity…” Source: RevenueBase Database · checked Sep 21, 2026
23	Rmss LTD	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	501-1,000	28 contacts →
	Indirect evidence “RMSS Ltd is a reputable and trustworthy company that has seen significant growth in the last decade.” Source: RevenueBase Database · checked Sep 21, 2026
24	Beamsec	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	26 contacts →
	Partial evidence “BeamSec is a UK-based cybersecurity provider delivering autonomous agents for continuous compliance and AI-powered human risk management, eliminating thousands of manual hours…” Source: RevenueBase Database · checked Sep 21, 2026
25	Encode	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	25 contacts →
	Partial evidence “Encode is now part of Obrela Security Industries collectively delivering cutting edge Cyber Security Services, empowering organizations to better protect against cyber threats.” Source: RevenueBase Database · checked Sep 21, 2026

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: AI security 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 AI security firms.
Partial evidence: Its own public description names part of AI security firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name AI security 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 261 AI security firms based in the United Kingdom

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AI security firms based in the United Kingdom at a glance

As of Sep 21, 2026

53.2%Verified-email coverage

49.3Average contacts per company

11-50Median size (employees)

47.9%Largest-city concentration · London

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

121

11-50

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 261 companies.

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 AI security 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 “AI security 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 AI security 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 AI security 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, 6,840 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 21, 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.

AI security firms by metro

AI security firms in London125

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 AI security 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 AI security firms are there based in the United Kingdom?

RevenueBase identified 261 AI security 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 AI security firms?

London leads with 125 headquartered companies, followed by Manchester (9) and Birmingham (6).

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 6,840 verified decision-maker contacts tracked across these 261 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 21, 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.