Company lists · Data refreshed September 2026

Top 25 Cybersecurity agencies based in the United Kingdom

Name: Cybersecurity agencies 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 1,586 companies tracked

RevenueBase identified 1,586 cybersecurity agencies headquartered in the United Kingdom as of September 2026 and tracks 28,759 professional contacts across them, including 11,085 with verified work emails. London is the largest hub.

This list covers cybersecurity agencies 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

1,586Companies

28,759Contacts tracked

11,085Verified emails

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The 25 largest cybersecurity agencies based in the United Kingdom

Ranked by team size

Top 25 of 1,586 cybersecurity agencies 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 cybersecurity agencies: 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	Strong evidence	Abingdon, United KingdomHQ checked Sep 21, 2026	5,001-10,000	4,925 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 21, 2026
2	Darktrace	Strong evidence	Cambridge, United KingdomHQ checked Sep 21, 2026	1,001-5,000	2,355 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 21, 2026
3	MTI	Indirect evidence	Staines-upon-thames, United KingdomHQ checked Sep 21, 2026	201-500	764 contacts →
	Indirect evidence “MTI provides award-winning, end-to-end technology solutions and services in cyber security and data centre for over 35 years.” Source: RevenueBase Database · checked Sep 21, 2026
4	Securityhq	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	501-1,000	502 contacts →
	Strong evidence “SecurityHQ, a global cybersecurity company pioneering Security Performance Engineering for stronger operational performance and resilience.” Source: RevenueBase Database · checked Sep 21, 2026
5	S-Rm	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	351 contacts →
	Indirect evidence “S-RM is a global intelligence and cyber security consultancy.” Source: RevenueBase Database · checked Sep 21, 2026
6	Reliance Infosystems	Indirect evidence	West End, United KingdomHQ checked Sep 21, 2026	201-500	326 contacts →
	Indirect evidence “As our name suggests, our customers rely on us in providing suitable technology inputs to support their business goals.” Source: RevenueBase Database · checked Sep 21, 2026
7	Bridewell	Indirect evidence	Reading, United KingdomHQ checked Sep 21, 2026	201-500	303 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 21, 2026
8	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
9	Xalient	Indirect evidence	Leeds, United KingdomHQ checked Sep 21, 2026	201-500	260 contacts →
	Indirect evidence “We are a global boutique, specializing exclusively in the convergence of identity-driven security and networking.” Source: RevenueBase Database · checked Sep 21, 2026
10	Obrela	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	242 contacts →
	Indirect evidence “Obrela Security Industries is a global provider of cyber security services.” Source: RevenueBase Database · checked Sep 21, 2026
11	IBM Sixworks	Indirect evidence	Farnborough, United KingdomHQ checked Sep 21, 2026	201-500	190 contacts →
	Indirect evidence “IBM SiXworks is a leading provider of secure digital solutions, specialising in digital experimentation and focused on fail-safe-fast cutting-edge technology solutions deployed in…” Source: RevenueBase Database · checked Sep 21, 2026
12	Deepcytes Cyber Labs UK	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	177 contacts →
	Indirect evidence “Whether you’re a business or an individual, digital threats to your precious data and assets can come in any form - external or internal.” Source: RevenueBase Database · checked Sep 21, 2026
13	Sapphire	Indirect evidence	Newcastle Upon Tyne, United KingdomHQ checked Sep 21, 2026	51-200	168 contacts →
	Indirect evidence “Sapphire delivers comprehensive cyber solutions tailored to your needs, spanning across consultancy, managed services, IT/OT and beyond.” Source: RevenueBase Database · checked Sep 21, 2026
14	Exclusive Networks UK	Strong evidence	Alton, United KingdomHQ checked Sep 21, 2026	201-500	165 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 21, 2026
15	Fournet	Indirect evidence	Manchester, United KingdomHQ checked Sep 21, 2026	201-500	165 contacts →
	Indirect evidence “FourNet transforms the customer and citizen services people rely on every day.” Source: RevenueBase Database · checked Sep 21, 2026
16	Cyberfort	Indirect evidence	Thatcham, United KingdomHQ checked Sep 21, 2026	51-200	159 contacts →
	Indirect evidence “At Cyberfort we are passionate about the cyber security services we deliver for our customers which keeps their people, data, systems and technology infrastructure secure…” Source: RevenueBase Database · checked Sep 21, 2026
17	Performanta	Strong evidence	Maidenhead, United KingdomHQ checked Sep 21, 2026	51-200	156 contacts →
	Strong evidence “Performanta is a global cybersecurity and data risk management company dedicated to protecting people where data matters most.” Source: RevenueBase Database · checked Sep 21, 2026
18	LOGIQ	Indirect evidence	Bradley Stoke, United KingdomHQ checked Sep 21, 2026	201-500	143 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 21, 2026
19	CCL Solutions Group	Indirect evidence	Stratford Upon Avon, United KingdomHQ checked Sep 21, 2026	51-200	138 contacts →
	Indirect evidence “CCL Solutions Group is one of Europe’s leading digital forensics, digital investigation and cyber security specialists, supporting law enforcement, government agencies, military…” Source: RevenueBase Database · checked Sep 21, 2026
20	Khipu Networks	Indirect evidence	Fleet, United KingdomHQ checked Sep 21, 2026	51-200	125 contacts →
	Indirect evidence “KHIPU Networks is an award winning international Cyber Security Company delivering a wide range of network, wireless and security solutions, technologies and services across…” Source: RevenueBase Database · checked Sep 21, 2026
21	Bulletproof Cyber Security	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	123 contacts →
	Indirect evidence “Bulletproof is now part of WorkNest Secure.” Source: RevenueBase Database · checked Sep 21, 2026
22	Friend MTS	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	120 contacts →
	Strong evidence “As the number one anti-piracy provider, Friend MTS is the trusted cybersecurity partner of the biggest brands in media, sports, and entertainment.” Source: RevenueBase Database · checked Sep 21, 2026
23	Protection Group International	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	118 contacts →
	Indirect evidence “PGI helps organisations build digital resilience.” Source: RevenueBase Database · checked Sep 21, 2026
24	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
25	Consortio Security	Indirect evidence	Castle Donington, United KingdomHQ checked Sep 21, 2026	501-1,000	106 contacts →
	Indirect evidence “Protecting People, Property, Assets & Brands.” 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: cybersecurity agencies. 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 agencies.
Partial evidence: Its own public description names part of cybersecurity agencies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name cybersecurity agencies. 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 1,586 cybersecurity agencies based in the United Kingdom

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Cybersecurity agencies based in the United Kingdom at a glance

As of Sep 21, 2026

38.5%Verified-email coverage

18.1Average contacts per company

1-10Median size (employees)

40.4%Largest-city concentration · London

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

941

11-50

457

51-200

125

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

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 1,586 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 cybersecurity agencies, 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 agencies”. 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 agencies), 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 agencies, 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, 11,085 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.

Cybersecurity agencies 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 agencies, 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 agencies are there based in the United Kingdom?

RevenueBase identified 1,586 cybersecurity agencies 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 agencies?

London leads with 641 headquartered companies, followed by Manchester (63) and Birmingham (34).

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 11,085 verified decision-maker contacts tracked across these 1,586 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.