Company lists · Data verified August 2026
Top 25 Cybersecurity companies in the United Kingdom
Our directory lists 2,111 cybersecurity companies in the United Kingdom, with 48,444 professional contacts and 18,121 email addresses. The list was last updated in August 2026, and London is the single most-represented city among the companies listed.
Cybersecurity companies provide products and services that protect systems, networks, applications, devices, and data from unauthorized access, disruption, or misuse. This list covers companies that provide cybersecurity products, services, consulting, assessments, monitoring, incident response, or related protection for digital systems and data. Ranked by employee count, largest first. Data current as of August 28, 2026.
The 25 largest cybersecurity companies in the United Kingdom
Ranked by employees| # | Company | Verified emails |
|---|---|---|
| 1 | Stroz Friedberg Limited | 0 |
| 2 | Assa Abloy | 0 |
| 3 |  Cyber & Specialist Operations Command | 0 |
| 4 |  Sailpoint | 1,979 |
| 5 |  Darktrace | 1,791 |
| 6 |  ROKE | 410 |
| 7 |  Notsosecure Training Part Of Claranet Cyber Security | 26 |
| 8 |  Attivo Networks , A Sentinelone Company | 21 |
| 9 |  Everfox | 13 |
| 10 | Notsosecure Training Part Of Claranet Cyber Security | 3 |
| 11 |  Trustwave Spider Labs | 2 |
| 12 |  Wolf Pack IT | 1 |
| 13 | Airbus Secure Communications | 1 |
| 14 | Claranet Cyber Security | 0 |
| 15 |  Netwrix Corporation | 550 |
| 16 |  Zerofox | 382 |
| 17 |  Yubico | 370 |
| 18 |  Withsecure | 329 |
| 19 |  Enea AB | 208 |
| 20 |  Integrity360 | 199 |
| 21 |  Claroty | 152 |
| 22 |  Wavenet Public Sector | 4 |
| 23 |  Cloud Guard Technologies | 3 |
| 24 | Arctic Wolf Network | 0 |
| 25 |  Kelltron Identity | 0 |
| 26 |  MYHSM | 0 |
| 27 |  Cyberitglobe | 0 |
| 28 | GSI | 0 |
Showing 25 of 2,111 cybersecurity companies in the United Kingdom
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Cybersecurity companies in the United Kingdom at a glance
As of Aug 28, 2026Companies by employee count
Companies by metro
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 companies”, with match quality audited by blind human judging, and headquartered in the United Kingdom.
- Ranking
- Employee count, largest first. Ranges reflect verified bands, not estimates.
- Verification
- Contact records re-verify on a rolling cadence; 185 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 companies are in the directory?
The directory lists 2,111 cybersecurity companies in the United Kingdom.
Which city has the most cybersecurity companies?
London is the single most-represented city among the cybersecurity companies on the list.
How many contacts are available for cybersecurity companies?
The directory includes 48,444 professional contacts and 18,121 email addresses for the listed cybersecurity companies.
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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.