Company lists · Data verified August 2026

Top 25 Cybersecurity software companies based in the United Kingdom

Name: Cybersecurity software companies 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 444 companies tracked

There are 444 cybersecurity software companies headquartered in the United Kingdom (RevenueBase, August 2026). RevenueBase tracks 14,437 professional contacts across them, including 7,036 with verified work emails and 2,263 with mobile numbers. London is the largest hub.

This list covers cybersecurity software companies 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.

444Companies

14,437Contacts tracked

7,036Verified emails

2,263Mobile numbers

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The 25 largest cybersecurity software companies based in the United Kingdom

Ranked by team size

Top 25 of 444 cybersecurity software companies 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	Darktrace	Cambridge	1,001-5,000	2,590	1,791
3	SISA	Leicester	201-500	739	253
4	Everfox	London	1,001-5,000	635	13
5	Withsecure	London	501-1,000	614	329
6	Bridewell	Edinburgh	201-500	304	189
7	Quorum Cyber	Edinburgh	201-500	292	177
8	Cyberfort	Thatcham	51-200	160	88
9	Cipher سايڤر	London	201-500	135	50
10	Khipu Networks	Fleet	51-200	129	94
11	Bulletproof Cyber Security	London	51-200	118	75
12	Foresite Cybersecurity	Farnborough	51-200	100	67
13	Drawbridge	London	51-200	97	60
14	Titania LTD	London	51-200	89	47
15	ITC Secure	London	51-200	87	39
16	Cybersmart	London	51-200	83	55
17	Reliance Cyber	Waterloo	51-200	80	47
18	TDI Tetrad Digital Integrity	Windsor	51-200	71	39
19	Becrypt	London	51-200	69	56
20	Eset UK	Bournemouth	51-200	66	41
21	Intruder	London	51-200	61	35
22	Garrison NOW A Part Of Everfox	London	51-200	59	2
23	Attivo Networks , A Sentinelone Company	Cambridge	1,001-5,000	57	21
24	Cloudmark	London	51-200	54	18
25	Hexegic	London	51-200	52	30

Showing 25 of 444 cybersecurity software companies based in the United Kingdom

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Cybersecurity software companies based in the United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 199 HQs

2,263Contacts with mobile numbers

17Emails re-verified in last 30 days

Companies by employee count

1-10

232

11-50

141

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

Cybersecurity software companies by metro

Metro	Companies
Cybersecurity software companies in London	199
Cybersecurity software companies in Manchester	16
Cybersecurity software companies in Cheltenham	10
Cybersecurity software companies in Birmingham	6
Cybersecurity software companies in Glasgow	6
Cybersecurity software companies in Cambridge	6
Cybersecurity software companies in Edinburgh	6

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 software companies”, 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; 17 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 software companies are there based in the United Kingdom?

There are 444 cybersecurity software companies 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 software companies?

London leads with 199 headquartered companies, followed by Manchester (16) and Cheltenham (10).

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 7,036 verified decision-maker contacts tracked across these 444 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.