Company lists · Data refreshed September 2026

Top 23 Security consultancies based in London, United Kingdom

Name: Security consultancies based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 21, 2026 1,559 companies tracked

RevenueBase identified 1,559 security consultancies headquartered in London, United Kingdom as of September 2026 and tracks 102,127 professional contacts across them, including 5,400 with verified work emails. London is the largest hub.

This list covers security consultancies headquartered in London, United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 21, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 21, 2026 86% judged on-target in blind review

1,559Companies

102,127Contacts tracked

5,400Verified emails

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The 23 largest security consultancies based in London, United Kingdom

Ranked by team size

Top 23 of 1,559 security consultancies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 21, 2026. RevenueBase Smart Search rates how each company's information relates to security consultancies: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	G4s	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	10001+	79,699 contacts →
	Partial evidence “G4S is a leading security and facility services company that provides proactive security services and cutting-edge smart technology to deliver tailored, integrated security…” Source: RevenueBase Database · checked Sep 21, 2026
2	Control Risks	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	2,972 contacts →
	Indirect evidence “Control Risks is a global specialist risk consultancy that helps to create secure, compliant and resilient organisations.” Source: RevenueBase Database · checked Sep 21, 2026
3	CIS Security Limited	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	919 contacts →
	Partial evidence “CIS Security is an independent security company equipped to help customers to solve the complex challenges in today’s digital, connected and regulated business world.” Source: RevenueBase Database · checked Sep 21, 2026
4	Corps Security	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	847 contacts →
	Partial evidence “Corps Security - experts in security with social value Built on over 165 years of experience, Corps provides specialist security services, across the UK, to ensure the safety of…” Source: RevenueBase Database · checked Sep 21, 2026
5	COBRA	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	n/a	705 contacts →
	Strong evidence “Get a free, powerful security assessment with personalised recommendations, the same analysis that costs from IT Consultancies.” Source: RevenueBase Database · checked Sep 21, 2026
6	Ward Security	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	419 contacts →
	Partial evidence “Ward is an award winning, privately owned business, providing bespoke risk and security solutions including protective security personnel, explosive search dogs, narcotic search…” Source: RevenueBase Database · checked Sep 21, 2026
7	Argenbright Security Europe Limited - Asel	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	5,001-10,000	358 contacts →
	Partial evidence “ASEL design, develop and deliver fully bespoke and integrated security solutions, seamlessly bringing together people, technology and processes to achieve results-driven outcomes.” Source: RevenueBase Database · checked Sep 21, 2026
8	S-Rm	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	351 contacts →
	Partial evidence “S-RM is a global intelligence and cyber security consultancy.” Source: RevenueBase Database · checked Sep 21, 2026
9	Obrela	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	242 contacts →
	Partial evidence “Obrela Security Industries is a global provider of cyber security services.” Source: RevenueBase Database · checked Sep 21, 2026
10	CT Group	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	233 contacts →
	Indirect evidence “CT Group is a global consultancy that uniquely combines research, intelligence, campaigns and advisory services, to deliver the results our clients need.” Source: RevenueBase Database · checked Sep 21, 2026
11	Interr	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	232 contacts →
	Indirect evidence “Established in 1994, Interr is a specialist agency providing intelligent guarding, reception, remote monitoring & response and front of house solutions within the retail, hotel…” Source: RevenueBase Database · checked Sep 21, 2026
12	QCIC	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	159 contacts →
	Partial evidence “QCIC is an award-winning global engineering firm specialising in designing, building and running security systems.” Source: RevenueBase Database · checked Sep 21, 2026
13	Tetra Consulting	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	153 contacts →
	Indirect evidence “At Tetra, we make buildings safer for people.” Source: RevenueBase Database · checked Sep 21, 2026
14	Turnkey Consulting	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	134 contacts →
	Partial evidence “Turnkey Consulting brings together people, protection, and performance to help the world’s leading companies understand and optimize their risk and security landscape.” Source: RevenueBase Database · checked Sep 21, 2026
15	Vigilant Security	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	1,001-5,000	133 contacts →
	Partial evidence “Vigilant Security provides a range of services including keyholding, corporate security, event security, mobile patrols as well as specialist services throughout the UK.” Source: RevenueBase Database · checked Sep 21, 2026
16	Trpglobal	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	126 contacts →
	Indirect evidence “We are TRPGLOBAL, your strategic partner in helping you with the complexities of risk management.” Source: RevenueBase Database · checked Sep 21, 2026
17	Bulletproof Cyber Security	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	123 contacts →
	Indirect evidence “Bulletproof is now part of WorkNest Secure.” Source: RevenueBase Database · checked Sep 21, 2026
18	Opticoreit	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	120 contacts →
	Indirect evidence “OpticoreIT is an IT Consultancy founded in 2013 to bridge a gap in the market between the major IT services providers and the consultancy market.” Source: RevenueBase Database · checked Sep 21, 2026
19	Protection Group International	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	118 contacts →
	Indirect evidence “PGI helps organisations build digital resilience.” Source: RevenueBase Database · checked Sep 21, 2026
20	FACT	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	117 contacts →
	Indirect evidence “FACT are at the forefront of investigative and intelligence services, recognised by organisations, law enforcement, and governments worldwide.” Source: RevenueBase Database · checked Sep 21, 2026
21	SSR Personnel	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	116 contacts →
	Partial evidence “SSR® Personnel is the largest recruitment consultancy & executive search practice dedicated to the security, fire, health and safety sectors.” Source: RevenueBase Database · checked Sep 21, 2026
22	Caretower An Integrity360 Company	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	97 contacts →
	Partial evidence “As an independent IT security specialist, Caretower provide comprehensive solutions to individual problems, thus allowing our recommendations to be unbiased.” Source: RevenueBase Database · checked Sep 21, 2026
23	AKE International	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	89 contacts →
	Indirect evidence “We are proud of our unique track record.” Source: RevenueBase Database · checked Sep 21, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: security consultancies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names security consultancies.
Partial evidence: Its own public description names part of security consultancies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name security consultancies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 23 of 1,559 security consultancies based in London, United Kingdom

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Security consultancies based in London, United Kingdom at a glance

As of Sep 21, 2026

5.3%Verified-email coverage

65.5Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · London

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

835

11-50

441

51-200

205

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Email recency for this list is measured across the whole United Kingdom list rather than for London, so it is reported there. Company counts and contact totals on this page are exact for London, over 1,559 companies.

How this list was built

Company categories are rarely black and white. RevenueBase reads each company's own description of its business to decide whether it belongs among security consultancies, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search rating on every row are there so you can check each match yourself.

Source: The RevenueBase company graph: 60 million companies and 398.9 million professional contacts resolved from primary sources, queried with RevenueBase Smart Search, the natural-language company search available to every RevenueBase user.
What qualifies: Companies headquartered in London, United Kingdom whose own description of what they do matches “security consultancies”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search: RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names security consultancies), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude: Companies whose own description does not clearly place them among security consultancies, and records with no verified work email. Companies headquartered outside London are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and its RevenueBase Smart Search rating so you can judge each match yourself. Read the full methodology: how the lists are built, how the judging worked, and what the figure means.
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: Every listed company carries at least one verified work email, 5,400 across the full list. Contacts re-verify on a rolling cadence, and each contact's own verification date is shown inside RevenueBase.
Refresh: This page's figures were pulled from the company graph on September 21, 2026. Lists refresh periodically as the graph is re-checked.
Corrections: Wrong category, wrong headquarters, or a company that has closed? Use “Report an issue” on any row. Reports go to the RevenueBase Data Team and feed back into the company graph.

Security consultancies by metro in the United Kingdom

Security consultancies in London1559
Security consultancies in Manchester132
Security consultancies in Birmingham101
Security consultancies in Leeds70
Security consultancies in Bristol65
Security consultancies in Glasgow59
Security consultancies in Liverpool49
Security consultancies in Reading44
Security consultancies in Cardiff41
Security consultancies in Edinburgh38
Security consultancies in Nottingham34
Security consultancies in Cambridge33
Security consultancies in Northampton31
Security consultancies in Belfast30
Security consultancies in Leicester30
Security consultancies in Southampton30
Security consultancies in Swindon30
Security consultancies in Cheltenham29
Security consultancies in Peterborough28
Security consultancies in Sheffield28

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names security consultancies, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

How many security consultancies are there based in London, United Kingdom?

RevenueBase identified 1,559 security consultancies headquartered in London, United Kingdom as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

G4s, headquartered in London, tops this list with the largest team on record.

Which city has the most security consultancies?

London leads with 1559 headquartered companies, followed by Manchester (132) and Birmingham (101).

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 5,400 verified decision-maker contacts tracked across these 1,559 companies.

How current is this list?

The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 21, 2026.

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About this data

RevenueBase is a B2B data infrastructure company. Its company graph covers 60 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 with RevenueBase Smart Search, the same natural-language company search every RevenueBase user has: describe a market in plain words, get the companies that match, and add verified emails and direct dials for the people at them. It is the same data that powers RevenueBase's B2B data products, and a free account includes 500 credits to start. How these lists are built and judged.