Company lists · Data verified August 2026

Top 25 Data security consulting firms based in the United Kingdom

Name: Data security 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 1,194 companies tracked

There are 1,194 data security consulting firms headquartered in the United Kingdom (RevenueBase, August 2026). RevenueBase tracks 9,824 professional contacts across them, including 2,984 with verified work emails and 549 with mobile numbers. London is the largest hub.

This list covers data security 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.

1,194Companies

9,824Contacts tracked

2,984Verified emails

549Mobile numbers

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The 25 largest data security consulting firms based in the United Kingdom

Ranked by team size

Top 25 of 1,194 data security 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	SISA	Leicester	201-500	739	253
2	Resillion	Glasgow	501-1,000	387	203
3	Ibridge, LLC	London	501-1,000	183	35
4	Risk Associates - Emea & Asia	London	51-200	169	62
5	Sapphire	Newcastle Upon Tyne	51-200	165	59
6	Cyberfort	Thatcham	51-200	160	88
7	Cybersec Consulting	London	201-500	141	76
8	Trpglobal	London	51-200	123	36
9	Bulletproof Cyber Security	London	51-200	118	75
10	Cybersrc Consultancy	London	51-200	99	39
11	Caretower An Integrity360 Company	London	201-500	97	12
12	ITC Secure	London	51-200	87	39
13	Cognisys	Leeds	51-200	85	48
14	Reliance Cyber	Waterloo	51-200	80	47
15	URM	Reading	51-200	80	38
16	Saepio Information Security	High Wycombe	51-200	73	57
17	Evalian	Worcester	51-200	61	39
18	Daintta	London	51-200	61	18
19	SQR Group Security Solutions LTD	Barnet	501-1,000	60	7
20	Cyberlab	Lincoln	51-200	56	41
21	Hexegic	London	51-200	52	30
22	Frankton Group LTD	London	51-200	47	9
23	Cornerstone	London	51-200	44	21
24	Mitigo Group	Cheadle	51-200	42	18
25	Lowers & Associates	London	51-200	39	17

Showing 25 of 1,194 data security consulting firms based in the United Kingdom

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Data security consulting firms based in the United Kingdom at a glance

As of Aug 28, 2026

1-10Median size (employees)

LondonLargest hub · 449 HQs

549Contacts with mobile numbers

2Emails re-verified in last 30 days

Companies by employee count

1-10

825

11-50

273

51-200

201-500

501-1,000

5,001-10,000

Data security consulting firms by metro

Metro	Companies
Data security consulting firms in London	449
Data security consulting firms in Manchester	40
Data security consulting firms in Birmingham	24
Data security consulting firms in Reading	16
Data security consulting firms in Bristol	16
Data security consulting firms in Leeds	15
Data security consulting firms in Cambridge	14

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 “data security 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; 2 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 data security consulting firms are there based in the United Kingdom?

There are 1,194 data security consulting firms 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 data security consulting firms?

London leads with 449 headquartered companies, followed by Manchester (40) and Birmingham (24).

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 2,984 verified decision-maker contacts tracked across these 1,194 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.