Company lists · Data verified August 2026

Top 25 Cybersecurity consulting firms based in the United Kingdom

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

Compiled by the RevenueBase Data Team Verified Aug 28, 2026 2,021 companies tracked

There are 2,021 cybersecurity consulting firms headquartered in the United Kingdom (RevenueBase, August 2026). RevenueBase tracks 25,417 professional contacts across them, including 10,000 with verified work emails and 2,542 with mobile numbers. London is the largest hub.

This list covers cybersecurity consulting 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. Data current as of August 28, 2026.

2,021Companies

25,417Contacts tracked

10,000Verified emails

2,542Mobile numbers

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The 25 largest cybersecurity consulting firms based in the United Kingdom

Ranked by team size

Top 25 of 2,021 cybersecurity consulting firms based in the United Kingdom, ranked by team size, largest first. Data verified Aug 28, 2026. Click a count to unlock that company's people.
#	Company	HQ	Employees	Contacts	Verified emails
1	Sophos	Abingdon	5,001-10,000	4,963	2,711
2	SISA	Leicester	201-500	739	253
3	Everfox	London	1,001-5,000	635	13
4	Withsecure	London	501-1,000	614	329
5	Integrity360	London	501-1,000	341	199
6	Bridewell	Edinburgh	201-500	304	189
7	Quorum Cyber	Edinburgh	201-500	292	177
8	Waterstons	Durham	201-500	223	157
9	The Redesign Group	London	201-500	201	140
10	Intragen	London	201-500	188	128
11	Fournet	Derby	201-500	173	115
12	Exclusive Networks UK	Mansfield	201-500	168	118
13	Cyberfort	Thatcham	51-200	160	88
14	LOGIQ	Bristol	201-500	142	81
15	Cybersec Consulting	London	201-500	141	76
16	CCL Solutions Group	Stratford Upon Avon	51-200	136	68
17	Cipher سايڤر	London	201-500	135	50
18	Khipu Networks	Fleet	51-200	129	94
19	Trpglobal	London	51-200	123	36
20	Cyberone	London	51-200	96	39
21	Wavenet Cyberguard	London	201-500	86	58
22	Reliance Cyber	Waterloo	51-200	80	47
23	URM	Reading	51-200	80	38
24	Baseel Partners	London	1,001-5,000	78	26
25	Synoptix	Bristol	51-200	76	11

Showing 25 of 2,021 cybersecurity consulting firms based in the United Kingdom

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Cybersecurity consulting firms based in the United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 799 HQs

2,542Contacts with mobile numbers

20Emails re-verified in last 30 days

Companies by employee count

1-10

1,290

11-50

535

51-200

131

201-500

501-1,000

1,001-5,000

5,001-10,000

Cybersecurity consulting firms by metro

Metro	Companies
Cybersecurity consulting firms in London	799
Cybersecurity consulting firms in Manchester	63
Cybersecurity consulting firms in Birmingham	38
Cybersecurity consulting firms in Cheltenham	29
Cybersecurity consulting firms in Leeds	25
Cybersecurity consulting firms in Cambridge	22
Cybersecurity consulting firms in Bristol	21

How this list was built

Source: The RevenueBase company graph: 21.3 million companies and 398.9 million professional contacts resolved from primary sources.
Inclusion: Companies whose own business descriptions match “cybersecurity consulting firms”, with match quality audited by blind human judging, and headquartered in the United Kingdom.
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: Contact records re-verify on a rolling cadence; 20 contacts on this list were re-verified in the last 30 days.
Refresh: Lists are refreshed periodically as the underlying company graph is re-verified. Last verified Aug 28, 2026.

Frequently asked

How many cybersecurity consulting firms are there based in the United Kingdom?

There are 2,021 cybersecurity consulting firms headquartered in the United Kingdom as of August 2026 (RevenueBase).

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 consulting firms?

London leads with 799 headquartered companies, followed by Manchester (63) and Birmingham (38).

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 10,000 verified decision-maker contacts tracked across these 2,021 companies.

How current is this list?

The list is refreshed periodically as the underlying company graph is re-verified. It was last verified on August 28, 2026.

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About this data

RevenueBase is a B2B contact data platform. Its company graph covers 21.3 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, the same data that powers RevenueBase's B2B data products and the free research portal.