Company lists · Data verified August 2026

Top 25 Cybersecurity audit companies based in the United Kingdom

Name: Cybersecurity audit 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 802 companies tracked

There are 802 cybersecurity audit companies headquartered in the United Kingdom (RevenueBase, August 2026). RevenueBase tracks 8,333 professional contacts across them, including 2,440 with verified work emails and 528 with mobile numbers. London is the largest hub.

This list covers cybersecurity audit 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.

802Companies

8,333Contacts tracked

2,440Verified emails

528Mobile numbers

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The 25 largest cybersecurity audit companies based in the United Kingdom

Ranked by team size

Top 25 of 802 cybersecurity audit 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	SISA	Leicester	201-500	739	253
2	Risk Associates - Emea & Asia	London	51-200	169	62
3	Cyberfort	Thatcham	51-200	160	88
4	Cybersec Consulting	London	201-500	141	76
5	Khipu Networks	Fleet	51-200	129	94
6	Trpglobal	London	51-200	123	36
7	Bulletproof Cyber Security	London	51-200	118	75
8	Foresite Cybersecurity	Farnborough	51-200	100	67
9	Caretower An Integrity360 Company	London	201-500	97	12
10	ITC Secure	London	51-200	87	39
11	Cybersmart	London	51-200	83	55
12	Reliance Cyber	Waterloo	51-200	80	47
13	Saepio Information Security	High Wycombe	51-200	73	57
14	TDI Tetrad Digital Integrity	Windsor	51-200	71	39
15	CSA Cyber	Gloucester	51-200	68	31
16	Covertswarm	London	51-200	65	41
17	Cyro Cyber	London	51-200	63	10
18	Evalian	Worcester	51-200	61	39
19	Cyberlab	Lincoln	51-200	56	41
20	Hexegic	London	51-200	52	30
21	IS Partners	London	51-200	49	42
22	Mitigo Group	Cheadle	51-200	42	18
23	Coretech Security	Cheltenham	51-200	41	7
24	defense.com	Stevenage	51-200	32	13
25	Torrid Networks Limited	London	51-200	32	2

Showing 25 of 802 cybersecurity audit companies based in the United Kingdom

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Cybersecurity audit companies based in the United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 330 HQs

528Contacts with mobile numbers

4Emails re-verified in last 30 days

Companies by employee count

1-10

503

11-50

222

51-200

201-500

501-1,000

1,001-5,000

5,001-10,000

Cybersecurity audit companies by metro

Metro	Companies
Cybersecurity audit companies in London	330
Cybersecurity audit companies in Manchester	31
Cybersecurity audit companies in Birmingham	20
Cybersecurity audit companies in Cheltenham	15
Cybersecurity audit companies in Cambridge	11
Cybersecurity audit companies in Leeds	9
Cybersecurity audit companies in Bristol	9

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 audit 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; 4 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 audit companies are there based in the United Kingdom?

There are 802 cybersecurity audit companies headquartered in the United Kingdom as of August 2026 (RevenueBase).

What is the largest company on this list?

SISA, headquartered in Leicester, tops this list with the largest team on record.

Which city has the most cybersecurity audit companies?

London leads with 330 headquartered companies, followed by Manchester (31) and Birmingham (20).

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 2,440 verified decision-maker contacts tracked across these 802 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.