Company lists · Data refreshed September 2026

Top 23 Security monitoring services based in London, United Kingdom

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

Compiled by the RevenueBase Data Team Data refreshed Sep 13, 2026 308 companies tracked

RevenueBase identified 308 security monitoring services headquartered in London, United Kingdom as of September 2026 and tracks 3,502 professional contacts across them, including 654 with verified work emails and 226 with mobile numbers. London is the largest hub.

This list covers security monitoring services 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 13, 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 13, 2026 86% judged on-target in blind review

308Companies

3,502Contacts tracked

654Verified emails

226Mobile numbers

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The 23 largest security monitoring services based in London, United Kingdom

Ranked by team size

Top 23 of 308 security monitoring services based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 13, 2026. RevenueBase Smart Search rates how each company's information relates to security monitoring services: 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	Obrela	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	201-500	242 contacts →
	Partial evidence “Obrela Security Industries is a global provider of cyber security services.” Source: RevenueBase Database · checked Sep 13, 2026
2	Deepcytes Cyber Labs UK	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	177 contacts →
	Indirect evidence “Whether you’re a business or an individual, digital threats to your precious data and assets can come in any form - external or internal.” Source: RevenueBase Database · checked Sep 13, 2026
3	The Keyholding Company	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	137 contacts →
	Partial evidence “The Keyholding Company are a tech-enabled mobile security services company, specialising in alarm response, mobile patrols, locks and unlocks, emergency and temporary guarding…” Source: RevenueBase Database · checked Sep 13, 2026
4	Cybersmart	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	84 contacts →
	Indirect evidence “Cybersecurity should be simple.” Source: RevenueBase Database · checked Sep 13, 2026
5	City Security Services Part Of City Group Security	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	201-500	64 contacts →
	Partial evidence “City Security Services (CSS) have more than 25 years’ experience within the corporate security, public sector, education and social housing markets delivering manned guarding…” Source: RevenueBase Database · checked Sep 13, 2026
6	WLS	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	61 contacts →
	Partial evidence “WLS (West London Security) has been providing security and solutions to London's homes and businesses for over 40 years.” Source: RevenueBase Database · checked Sep 13, 2026
7	Black Diamond Security	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	201-500	58 contacts →
	Partial evidence “Black Diamond Security - Safeguarding Your World.” Source: RevenueBase Database · checked Sep 13, 2026
8	Hexegic	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	52 contacts →
	Indirect evidence “At Hexegic we are not just passionate about protecting data through our Cyber services we are passionate about helping companies release the potential of the data they hold…” Source: RevenueBase Database · checked Sep 13, 2026
9	Redscan, A Kroll Business	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	51 contacts →
	Partial evidence “Redscan is an award-winning provider of managed security services, specialising in Managed Detection and Response, Penetration Testing and Red Teaming.” Source: RevenueBase Database · checked Sep 13, 2026
10	Frankton Group LTD	Indirect evidence	London, United KingdomHQ checked Sep 13, 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 13, 2026
11	Ak9 Security And FM Solutions LTD	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	501-1,000	43 contacts →
	Partial evidence “AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.” Source: RevenueBase Database · checked Sep 13, 2026
12	CYJAX	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	29 contacts →
	Indirect evidence “CYJAX is an award-winning technology company and provider of digital threat intelligence services to international corporations, law enforcement agencies and the public sector.” Source: RevenueBase Database · checked Sep 13, 2026
13	Nanjgel Solutions	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	24 contacts →
	Partial evidence “Nanjgel Solutions is focused on delivering the best IT security for businesses.” Source: RevenueBase Database · checked Sep 13, 2026
14	Toro Solutions	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	11-50	23 contacts →
	Indirect evidence “Toro was founded on creating the UK's first Red Team penetration test - and then attacking hundreds of clients by hacking their systems, influencing / social engineering staff and…” Source: RevenueBase Database · checked Sep 13, 2026
15	Templar Executives	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	21 contacts →
	Partial evidence “Templar Executives is an award winning, international Cyber Security advisory services and solutions company operating at the highest levels across the public and private sectors.” Source: RevenueBase Database · checked Sep 13, 2026
16	NGS Next Generation Security	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	11-50	20 contacts →
	Partial evidence “Formed in 2018, NGS (UK) Ltd are independent, Next Generation Security trusted advisors, providing all-encompassing solutions from the perimeter to the endpoint.” Source: RevenueBase Database · checked Sep 13, 2026
17	Secure Purple	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	11-50	20 contacts →
	Partial evidence “Secure Purple is a leading cyber security and digital safety firm that provides innovative solutions and services to help organisations and individuals stay protected in the…” Source: RevenueBase Database · checked Sep 13, 2026
18	Sinevis	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	11-50	17 contacts →
	Indirect evidence “We are a leading cybersecurity services organization with more than a decade of proven expertise in consulting, solution implementation and managed services.” Source: RevenueBase Database · checked Sep 13, 2026
19	CST Limited Computer Security Technology	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	11-50	17 contacts →
	Partial evidence “We are a London based specialist supplier of cyber defence solution and information security services.” Source: RevenueBase Database · checked Sep 13, 2026
20	Barefoot Cyber	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	11-50	16 contacts →
	Indirect evidence “Barefoot Cyber is the strategic partner for senior leaders who recognize that a cybersecurity attack is not just a technical failure, but a direct threat to their revenue…” Source: RevenueBase Database · checked Sep 13, 2026
21	SSG Support Services Group LTD	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	201-500	16 contacts →
	Partial evidence “SSG Support Services Group LTD is specialists in provision of Manned guarding Security Services, Door Supervision, Security Guarding, Out of Hours Support, Concierge, Front of…” Source: RevenueBase Database · checked Sep 13, 2026
22	Integrated Visual Protection Limited	Partial evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	16 contacts →
	Partial evidence “Integrated Visual Protection Limited (IVP) is a privately owned Company, which has been established since 2002, providing all types of Fire and Security Services to a variety of…” Source: RevenueBase Database · checked Sep 13, 2026
23	Datasixth Consulting	Indirect evidence	London, United KingdomHQ checked Sep 13, 2026	51-200	15 contacts →
	Indirect evidence “Who We Are DataSixth delivers Cybersecurity Intelligence.” Source: RevenueBase Database · checked Sep 13, 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 monitoring services. 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 monitoring services.
Partial evidence: Its own public description names part of security monitoring services, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name security monitoring services. 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 308 security monitoring services based in London, United Kingdom

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Security monitoring services based in London, United Kingdom at a glance

As of Sep 13, 2026

18.7%Verified-email coverage

6.5%Mobile-number coverage

11.4Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · London

Sep 13, 2026Page data refreshed

Companies by employee count

1-10

158

11-50

51-200

201-500

501-1,000

1,001-5,000

10001+

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 16.0d

5210–30

12931–60

261–90

190–180

1180+

Company record updated

Median 77.0d

00–30

1,02131–60

1,80361–90

50590–180

173180+

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 monitoring services, 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 monitoring services”. 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 monitoring services), 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 monitoring services, 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, 654 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 13, 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 monitoring services by metro in the United Kingdom

Security monitoring services in London308
Security monitoring services in Manchester45

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 monitoring services, 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 monitoring services are there based in London, United Kingdom?

RevenueBase identified 308 security monitoring services 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?

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

Which city has the most security monitoring services?

London leads with 308 headquartered companies, followed by Manchester (45) 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 654 verified decision-maker contacts tracked across these 308 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 13, 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.