Company lists · Data refreshed September 2026

Top 25 AI security firms based in London, United Kingdom

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

Compiled by the RevenueBase Data Team Data refreshed Sep 24, 2026 113 companies tracked

RevenueBase identified 113 AI security firms headquartered in London, United Kingdom as of September 2026 and tracks 3,555 professional contacts across them, including 1,735 with verified work emails and 706 with mobile numbers. Across the United Kingdom, London is the largest hub for this category.

This list covers AI security firms headquartered in London, 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 24, 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 24, 2026 86% judged on-target in blind review

113Companies

3,555Contacts tracked

1,735Verified emails

706Mobile numbers

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The 25 largest AI security firms based in London, United Kingdom

Ranked by team size

Top 25 of 113 AI security firms based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 24, 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	Mimecast	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	1,001-5,000	2,304 contacts →
	Indirect evidence “organizations.” Source: RevenueBase Database · checked Sep 24, 2026
2	QODEA	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	201-500	231 contacts →
	Partial evidence “Qodea, powered by Beyond, are a technology group building the world's leading cloud and cybersecurity solutions, from foundational infrastructure to advanced AI.” Source: RevenueBase Database · checked Sep 24, 2026
3	RED Sift	Indirect evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
4	Threatspike	Strong evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
5	Senseon	Indirect evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
6	Gratte Brothers Security Systems & Software	Partial evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
7	Redhunt Labs	Strong evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	36 contacts →
	Strong evidence “RedHunt Labs is a research-driven cybersecurity company delivering Continuous Threat Exposure Management (CTEM), PTaaS, and AI Exposure Security.” Source: RevenueBase Database · checked Sep 24, 2026
8	Nothreat	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	36 contacts →
	Partial evidence “The future of IoT/OT security is here.” Source: RevenueBase Database · checked Sep 24, 2026
9	Rmss LTD	Indirect evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
10	Beamsec	Partial evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
11	Encode	Partial evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
12	Vulnhero	Strong evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	16 contacts →
	Strong evidence “VulnHero is an AI-driven continuous full-stack offensive security platform that helps teams see what scanners miss and focus on exploitable risk first.” Source: RevenueBase Database · checked Sep 24, 2026
13	Runecast Solutions	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	51-200	15 contacts →
	Indirect evidence “Runecast Solutions Ltd.” Source: RevenueBase Database · checked Sep 24, 2026
14	Netrascale	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	15 contacts →
	Indirect evidence “At NetraScale, we help businesses navigate the ever-evolving cybersecurity landscape with confidence.” Source: RevenueBase Database · checked Sep 24, 2026
15	Everycloud AI & Data Security	Strong evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	14 contacts →
	Strong evidence “Demand more from your AI & Data Security partner.” Source: RevenueBase Database · checked Sep 24, 2026
16	LEO Cybsec	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	14 contacts →
	Partial evidence “Leo CybSec is the company behind Hoplon, an AI-powered cybersecurity platform designed for growing, data-driven businesses.” Source: RevenueBase Database · checked Sep 24, 2026
17	Vizgard	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	13 contacts →
	Partial evidence “Vizgard is a multi-award-winning SME building a safer future by automating real-time Security and Defence optical systems that traditionally require repetitive or prolonged…” Source: RevenueBase Database · checked Sep 24, 2026
18	Praeferre	Strong evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	13 contacts →
	Strong evidence “Praeferre is an AI-powered cybersecurity company, backed by SFC Capital, shaping the future of business security and compliance.” Source: RevenueBase Database · checked Sep 24, 2026
19	Ensl Group Ensl Cybertech LTD	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	11 contacts →
	Partial evidence “ENSL offers a range of Artificial Intelligence Driven Cyber-security and digital transformation services.” Source: RevenueBase Database · checked Sep 24, 2026
20	Cyberseer	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	8 contacts →
	Partial evidence “Cyberseer offers Advanced Threat Detection and a 24×7 Managed Security Service (MSS).” Source: RevenueBase Database · checked Sep 24, 2026
21	Elemendar- Making Intelligence Actionable	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	8 contacts →
	Indirect evidence “Elemendar develops Artificial Intelligence which reads cyber threat reports (CTI) authored by humans and instantly translates them into industry-standard machine-readable and…” Source: RevenueBase Database · checked Sep 24, 2026
22	Covenda Labs	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	8 contacts →
	Partial evidence “Covenda is AI cybersecurity with cutting-edge threat modeling and ML-powered risk prediction to counter cyber attacks on businesses.” Source: RevenueBase Database · checked Sep 24, 2026
23	Countershadow	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	7 contacts →
	Indirect evidence “CounterShadow is redefining the cybersecurity landscape as the future of agentic cybersecurity.” Source: RevenueBase Database · checked Sep 24, 2026
24	Priam Cyber AI	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	1-10	7 contacts →
	Partial evidence “Priam Cyber AI builds AVA (Advanced Virtual Analyst), an AI SOC platform that investigates alerts the way an analyst would.” Source: RevenueBase Database · checked Sep 24, 2026
25	Medicare Network	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	11-50	7 contacts →
	Indirect evidence “Medicare Network is a niche, agile cybersecurity and risk management company offering a range of industry-leading and advanced solutions that combines human intelligence…” Source: RevenueBase Database · checked Sep 24, 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 113 AI security firms based in London, United Kingdom

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AI security firms based in London, United Kingdom at a glance

As of Sep 24, 2026

48.8%Verified-email coverage

19.9%Mobile-number coverage

31.5Average contacts per company

11-50Median size (employees)

Sep 24, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

1,001-5,000

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 26.0d

1,3060–30

35131–60

1961–90

390–180

24180+

Company record updated

Median 69.0d

00–30

96331–60

1,71061–90

73690–180

231180+

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 London, 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 London 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, 1,735 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 24, 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.

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 London, United Kingdom?

RevenueBase identified 113 AI security firms headquartered in London, 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?

Mimecast, headquartered in London, tops this list with the largest team on record.

Which city in the United Kingdom has the most AI security firms?

London leads the United Kingdom 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 1,735 verified decision-maker contacts tracked across these 113 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 24, 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.