Company lists · Data refreshed September 2026

Top 25 Cybersecurity consultancies based in the United Kingdom

Name: Cybersecurity consultancies based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 24, 2026 4,932 companies tracked

RevenueBase identified 4,932 cybersecurity consultancies headquartered in the United Kingdom as of September 2026 and tracks 84,406 professional contacts across them, including 30,915 with verified work emails and 6,583 with mobile numbers. London is the largest hub.

This list covers cybersecurity consultancies 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 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

4,932Companies

84,406Contacts tracked

30,915Verified emails

6,583Mobile numbers

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The 25 largest cybersecurity consultancies based in the United Kingdom

Ranked by team size

Top 25 of 4,932 cybersecurity consultancies based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 24, 2026. RevenueBase Smart Search rates how each company's information relates to cybersecurity consultancies: 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 24, 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 24, 2026
2	Control Risks	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	1,001-5,000	2,972 contacts →
	Indirect evidence “Control Risks is a global specialist risk consultancy that helps to create secure, compliant and resilient organisations.” Source: RevenueBase Database · checked Sep 24, 2026
3	Darktrace	Partial evidence	Cambridge, United KingdomHQ checked Sep 24, 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 24, 2026
4	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
5	Hack The BOX	Partial evidence	Folkestone, United KingdomHQ checked Sep 24, 2026	n/a	1,975 contacts →
	Partial 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 24, 2026
6	Noventiq	Partial evidence	London, United KingdomHQ checked Sep 24, 2026	5,001-10,000	1,508 contacts →
	Partial evidence “Noventiq (Noventiq Holdings PLC) is a leading global solutions and services provider in digital transformation and cybersecurity, headquartered in London.” Source: RevenueBase Database · checked Sep 24, 2026
7	Frazer-Nash Consultancy	Indirect evidence	Leatherhead, United KingdomHQ checked Sep 24, 2026	1,001-5,000	1,437 contacts →
	Indirect evidence “With offices in the UK and Australia, Frazer-Nash is a leading systems, engineering and technology company.” Source: RevenueBase Database · checked Sep 24, 2026
8	CIS Security Limited	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	1,001-5,000	919 contacts →
	Indirect evidence “CIS Security is an independent security company equipped to help customers to solve the complex challenges in today’s digital, connected and regulated business world.” Source: RevenueBase Database · checked Sep 24, 2026
9	CTS	Indirect evidence	Manchester, United KingdomHQ checked Sep 24, 2026	201-500	844 contacts →
	Indirect evidence “We are the largest Google Cloud-only digital consultancy in Europe, and our mission is to change the way technology works for business.” Source: RevenueBase Database · checked Sep 24, 2026
10	MTI	Indirect evidence	Staines-upon-thames, United KingdomHQ checked Sep 24, 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 24, 2026
11	MASS	Indirect evidence	St Neots, United KingdomHQ checked Sep 24, 2026	201-500	640 contacts →
	Indirect evidence “MASS, part of the Cohort plc group, helps you realise the value of your data.” Source: RevenueBase Database · checked Sep 24, 2026
12	Dimension Data UKI	Indirect evidence	Fleet, United KingdomHQ checked Sep 24, 2026	1,001-5,000	540 contacts →
	Indirect evidence “Dimension Data uses the power of technology to help organisations achieve great things.” Source: RevenueBase Database · checked Sep 24, 2026
13	Securityhq	Partial evidence	London, United KingdomHQ checked Sep 24, 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 24, 2026
14	Analysys Mason	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	201-500	459 contacts →
	Indirect evidence “Analysys Mason is the leading specialist consultancy, creating lasting value in technology-intensive industries, including telecoms, digital infrastructure, software, IT services…” Source: RevenueBase Database · checked Sep 24, 2026
15	ACORA	Indirect evidence	Burgess Hill, United KingdomHQ checked Sep 24, 2026	501-1,000	423 contacts →
	Indirect evidence “We’ve been on a mission to bring together people and technology since the day we were founded over 25 years ago.” Source: RevenueBase Database · checked Sep 24, 2026
16	Lodge Security	Indirect evidence	Cirencester, United KingdomHQ checked Sep 24, 2026	1,001-5,000	422 contacts →
	Indirect evidence “Unlike traditional security providers, we're redefining what protection means in today's world.” Source: RevenueBase Database · checked Sep 24, 2026
17	Trustmarque	Indirect evidence	York, United KingdomHQ checked Sep 24, 2026	501-1,000	421 contacts →
	Indirect evidence “Trustmarque delivers the value of technology to bring real-life impact.” Source: RevenueBase Database · checked Sep 24, 2026
18	FSP	Indirect evidence	Reading, United KingdomHQ checked Sep 24, 2026	201-500	366 contacts →
	Indirect evidence “FSP is a leading consultancy specialising in Data and AI, Cyber Security, Enterprise Cloud and Change Delivery, providing advisory led enterprise transformation delivered through…” Source: RevenueBase Database · checked Sep 24, 2026
19	Littlefish	Indirect evidence	Nottingham, United KingdomHQ checked Sep 24, 2026	201-500	364 contacts →
	Indirect evidence “Littlefish is a multi-award-winning Managed IT Services Provider that continues to grow consistently and significantly through tangibly delivering on our promises of enhanced user…” Source: RevenueBase Database · checked Sep 24, 2026
20	Immersive	Indirect evidence	Bristol, United KingdomHQ checked Sep 24, 2026	201-500	352 contacts →
	Indirect evidence “The leader in people-centric cyber resilience.” Source: RevenueBase Database · checked Sep 24, 2026
21	S-Rm	Indirect evidence	London, United KingdomHQ checked Sep 24, 2026	201-500	351 contacts →
	Indirect evidence “S-RM is a global intelligence and cyber security consultancy.” Source: RevenueBase Database · checked Sep 24, 2026
22	Kings Secure Technologies	Indirect evidence	Bradford, United KingdomHQ checked Sep 24, 2026	501-1,000	326 contacts →
	Indirect evidence “Kings Secure Technologies (KST) is a high-end, enterprise-level systems integrator.” Source: RevenueBase Database · checked Sep 24, 2026
23	Reliance Infosystems	Indirect evidence	West End, United KingdomHQ checked Sep 24, 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 24, 2026
24	Bridewell	Indirect evidence	Reading, United KingdomHQ checked Sep 24, 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 24, 2026
25	Quorum Cyber	Indirect evidence	Edinburgh, United KingdomHQ checked Sep 24, 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 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: cybersecurity consultancies. 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 consultancies.
Partial evidence: Its own public description names part of cybersecurity consultancies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name cybersecurity consultancies. 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 4,932 cybersecurity consultancies based in the United Kingdom

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Cybersecurity consultancies based in the United Kingdom at a glance

As of Sep 24, 2026

36.6%Verified-email coverage

7.8%Mobile-number coverage

17.1Average contacts per company

1-10Median size (employees)

36.3%Largest-city concentration · London

Sep 24, 2026Page data refreshed

Companies by employee count

1-10

3,044

11-50

1,359

51-200

352

201-500

101

501-1,000

1,001-5,000

5,001-10,000

10001+

Freshness & accuracy

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

Email last verified

Median 26.0d

23,1710–30

7,05731–60

44261–90

1990–180

226180+

Company record updated

Median 87.0d

00–30

11,41331–60

40,33461–90

27,40590–180

5,254180+

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 consultancies, 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 consultancies”. 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 consultancies), 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 consultancies, 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, 30,915 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.

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

RevenueBase identified 4,932 cybersecurity consultancies 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 consultancies?

London leads with 1791 headquartered companies, followed by Manchester (143) and Birmingham (71).

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 30,915 verified decision-maker contacts tracked across these 4,932 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.