Company lists · Data refreshed September 2026

Top 25 Security consultancy companies based in London, United Kingdom

Name: Security consultancy companies 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 573 companies tracked

RevenueBase identified 573 security consultancy companies headquartered in London, United Kingdom as of September 2026 and tracks 9,459 professional contacts across them, including 1,448 with verified work emails. London is the largest hub.

This list covers security consultancy companies 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

573Companies

9,459Contacts tracked

1,448Verified emails

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The 25 largest security consultancy companies based in London, United Kingdom

Ranked by team size

Top 25 of 573 security consultancy companies 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 consultancy companies: 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	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
2	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
3	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
4	S-Rm	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	351 contacts →
	Strong evidence “S-RM is a global intelligence and cyber security consultancy.” Source: RevenueBase Database · checked Sep 21, 2026
5	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
6	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
7	SSR Personnel	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	116 contacts →
	Strong 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
8	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
9	Principle ONE	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	78 contacts →
	Partial evidence “Principle One provides Systems Engineering, Architecture and Business Consulting services within the Law Enforcement, National Security, Health and wider public sector.” Source: RevenueBase Database · checked Sep 21, 2026
10	Cyro Cyber	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	62 contacts →
	Partial evidence “Cyro Cyber are your cyber security Guardians.” Source: RevenueBase Database · checked Sep 21, 2026
11	Daintta	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	60 contacts →
	Indirect evidence “We provide deep expertise with technical and business specialists to help clients secure and protect the UK.” Source: RevenueBase Database · checked Sep 21, 2026
12	Black Diamond Security	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	58 contacts →
	Partial evidence “Black Diamond Security - Safeguarding Your World.” Source: RevenueBase Database · checked Sep 21, 2026
13	Custom Intelligent Security	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	51 contacts →
	Partial evidence “Established in Custom Intelligent Security is a technology driven ISO27001 & NSi Gold Accredited independent electronic security specialist with a proven track record of…” Source: RevenueBase Database · checked Sep 21, 2026
14	GSA Global	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	49 contacts →
	Partial evidence “GSA Global helps organisations, families and individuals respond to serious, complex and emerging security risks.” Source: RevenueBase Database · checked Sep 21, 2026
15	Frankton Group LTD	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	48 contacts →
	Indirect evidence “In today’s complex threat environment, businesses, individuals, and organisations require trusted partners to provide the ultimate assurance that their assets are well protected.” Source: RevenueBase Database · checked Sep 21, 2026
16	Cornerstone	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	44 contacts →
	Partial evidence “CornerStone is an award winning, independent, security and digital building consulting firm with headquarters in the UK.” Source: RevenueBase Database · checked Sep 21, 2026
17	Gratte Brothers Security Systems & Software	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	39 contacts →
	Partial evidence “Gratte Brothers is an experienced provider of integrated security solutions, which are Built on Strong Values and ultimately deliver a measurable return on investment.” Source: RevenueBase Database · checked Sep 21, 2026
18	Secforce LTD	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	39 contacts →
	Partial evidence “SECFORCE are vendor independent offensive security specialists providing effective business risk intelligence and strategic security consulting.” Source: RevenueBase Database · checked Sep 21, 2026
19	Audere Group	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	37 contacts →
	Indirect evidence “Audere Group is a London-headquartered holistic risk advisory company founded in 2014.” Source: RevenueBase Database · checked Sep 21, 2026
20	Skylark Security LTD	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	n/a	34 contacts →
	Partial evidence “Skylark is a bespoke security service provider based in London.” Source: RevenueBase Database · checked Sep 21, 2026
21	Security Risk Specialists LTD	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	33 contacts →
	Partial evidence “With headquarters in Central London and established in 2013, Security Risk Specialists (SRS) provides tailored Security and Concierge solutions across London.” Source: RevenueBase Database · checked Sep 21, 2026
22	Othrys	Indirect evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	33 contacts →
	Indirect evidence “Othrys is a global strategic and risk advisory firm founded in 2016.” Source: RevenueBase Database · checked Sep 21, 2026
23	Trigon Fire Safety	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	11-50	32 contacts →
	Partial evidence “As an independent fire safety consultancy, we thrive for highest quality of advice whilst ensuring life safety is always our priority.” Source: RevenueBase Database · checked Sep 21, 2026
24	Capstar	Partial evidence	London, United KingdomHQ checked Sep 21, 2026	51-200	30 contacts →
	Partial evidence “Capstar provides technology-enabled threat, risk and security services to private and corporate clients.” Source: RevenueBase Database · checked Sep 21, 2026
25	Universal Defence And Security Solutions	Strong evidence	London, United KingdomHQ checked Sep 21, 2026	201-500	29 contacts →
	Strong evidence “Defence and security services consultancy.” 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 consultancy companies. 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 consultancy companies.
Partial evidence: Its own public description names part of security consultancy companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name security consultancy companies. 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 25 of 573 security consultancy companies based in London, United Kingdom

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Security consultancy companies based in London, United Kingdom at a glance

As of Sep 21, 2026

15.3%Verified-email coverage

16.5Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · London

Sep 21, 2026Page data refreshed

Companies by employee count

1-10

322

11-50

156

51-200

201-500

501-1,000

1,001-5,000

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 573 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 consultancy companies, 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 consultancy companies”. 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 consultancy companies), 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 consultancy companies, 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, 1,448 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 consultancy companies by metro in the United Kingdom

Security consultancy companies in London573
Security consultancy companies in Manchester35
Security consultancy companies in Birmingham28

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 consultancy companies, 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 consultancy companies are there based in London, United Kingdom?

RevenueBase identified 573 security consultancy companies 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?

CIS Security Limited, headquartered in London, tops this list with the largest team on record.

Which city has the most security consultancy companies?

London leads with 573 headquartered companies, followed by Manchester (35) and Birmingham (28).

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 1,448 verified decision-maker contacts tracked across these 573 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.