Company lists · Data verified August 2026

Top 25 Cybersecurity service providers based in the United Kingdom

Name: Cybersecurity service providers 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 2,078 companies tracked

There are 2,078 cybersecurity service providers headquartered in the United Kingdom (RevenueBase, August 2026). RevenueBase tracks 29,720 professional contacts across them, including 12,537 with verified work emails and 2,984 with mobile numbers. London is the largest hub.

This list covers cybersecurity service providers 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.

2,078Companies

29,720Contacts tracked

12,537Verified emails

2,984Mobile numbers

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The 25 largest cybersecurity service providers based in the United Kingdom

Ranked by team size

Top 25 of 2,078 cybersecurity service providers 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	Zerofox	n/a	501-1,000	894	382
3	SISA	Leicester	201-500	739	253
4	Everfox	London	1,001-5,000	635	13
5	MASS	Lincoln	201-500	633	203
6	Withsecure	London	501-1,000	614	329
7	Littlefish	Nottingham	201-500	372	220
8	Integrity360	London	501-1,000	341	199
9	Bridewell	Edinburgh	201-500	304	189
10	Quorum Cyber	Edinburgh	201-500	292	177
11	Fluidone	London	201-500	202	165
12	The Redesign Group	London	201-500	201	140
13	Intragen	London	201-500	188	128
14	Fournet	Derby	201-500	173	115
15	Exclusive Networks UK	Mansfield	201-500	168	118
16	CSI LTD A CSI Group Company	London	201-500	161	116
17	LOGIQ	Bristol	201-500	142	81
18	Cybersec Consulting	London	201-500	141	76
19	Cipher سايڤر	London	201-500	135	50
20	Razorblue Group	Manchester	201-500	129	102
21	Wavenet Cyberguard	London	201-500	86	58
22	Daisy Corporate Services	Manchester	1,001-5,000	86	46
23	Bluecube Technology Solutions	Milton Keynes	201-500	73	39
24	Redsquid	Borehamwood	201-500	72	46
25	Izoologic	City Of London	201-500	67	48

Showing 25 of 2,078 cybersecurity service providers based in the United Kingdom

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Cybersecurity service providers based in the United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 773 HQs

2,984Contacts with mobile numbers

28Emails re-verified in last 30 days

Companies by employee count

1-10

1,229

11-50

609

51-200

154

201-500

501-1,000

1,001-5,000

5,001-10,000

Cybersecurity service providers by metro

Metro	Companies
Cybersecurity service providers in London	773
Cybersecurity service providers in Manchester	62
Cybersecurity service providers in Birmingham	33
Cybersecurity service providers in Cheltenham	27
Cybersecurity service providers in Bristol	23
Cybersecurity service providers in Leeds	21
Cybersecurity service providers in Glasgow	20

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 service providers”, 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; 28 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 service providers are there based in the United Kingdom?

There are 2,078 cybersecurity service providers 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 service providers?

London leads with 773 headquartered companies, followed by Manchester (62) and Birmingham (33).

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 12,537 verified decision-maker contacts tracked across these 2,078 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.