Company lists · Data refreshed September 2026

Top 24 Enterprise security system providers based in London, United Kingdom

Name: Enterprise security system providers based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 28, 2026 248 companies tracked

RevenueBase identified 248 enterprise security system providers headquartered in London, United Kingdom as of September 2026 and tracks 2,054 professional contacts across them, including 515 with verified work emails. Across the United Kingdom, London is the largest hub for this category.

This list covers enterprise security system providers 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 28, 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 28, 2026 86% judged on-target in blind review

248Companies

2,054Contacts tracked

515Verified emails

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The 24 largest enterprise security system providers based in London, United Kingdom

Ranked by team size

Top 24 of 248 enterprise security system providers based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to enterprise security system providers: 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	QCIC	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	159 contacts →
	Strong evidence “QCIC is an award-winning global engineering firm specialising in designing, building and running security systems.” Source: RevenueBase Database · checked Sep 28, 2026
2	The Keyholding Company	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
3	City Security Services Part Of City Group Security	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
4	WLS	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
5	Custom Intelligent Security	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
6	Electranet UK Limited	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	49 contacts →
	Indirect evidence “Electranet’s mission is to be a preferred partner to the public and private sectors, bringing competitively priced, secure and innovative solutions to the market.” Source: RevenueBase Database · checked Sep 28, 2026
7	Ak9 Security And FM Solutions LTD	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
8	Gratte Brothers Security Systems & Software	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
9	Universal Security Systems LTD	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	39 contacts →
	Strong evidence “Universal Security Systems Limited is a specialist provider of installation and maintenance services for all types of security systems including Access Control, Closed Circuit…” Source: RevenueBase Database · checked Sep 28, 2026
10	Videxuk	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	36 contacts →
	Partial evidence “We are the experts in door entry and access control and have been supplying and manufacturing systems for 40 years.” Source: RevenueBase Database · checked Sep 28, 2026
11	Pafi LTD	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	32 contacts →
	Partial evidence “Pafi Ltd, Was formed in 1995 to design, install and maintain integrated security solutions for the commercial market.” Source: RevenueBase Database · checked Sep 28, 2026
12	DS Security Group LTD	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	27 contacts →
	Partial evidence “CCTV and Access Control Service and installation specialists Established in 1993 DS Security prides itself on customer service.” Source: RevenueBase Database · checked Sep 28, 2026
13	Nanjgel Solutions	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	24 contacts →
	Partial evidence “Nanjgel Solutions is focused on delivering the best IT security for businesses.” Source: RevenueBase Database · checked Sep 28, 2026
14	Welcome Gate	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	23 contacts →
	Strong evidence “Who are you… Most likely you are a Workplace or IT Professional with a lot on your plate including physical electronic security systems, such as - Access control - CCTV - Intruder…” Source: RevenueBase Database · checked Sep 28, 2026
15	Dennis Johns Service Group	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	20 contacts →
	Indirect evidence “The Dennis Johns Service Group is a forward thinking group of companies providing, Electrical, CCTV and Access Control, installation and maintenance contracting services.” Source: RevenueBase Database · checked Sep 28, 2026
16	NGS Next Generation Security	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
17	The Portmarnock Group	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	19 contacts →
	Partial evidence “The Portmarnock Group was built from years of experience, hard work and a genuine passion for doing security differently.” Source: RevenueBase Database · checked Sep 28, 2026
18	SW Security Solutions LTD	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	17 contacts →
	Strong evidence “SW Security Solutions SA - Integrators of electronic security systems in 18 countries around the world.” Source: RevenueBase Database · checked Sep 28, 2026
19	SSG Support Services Group LTD	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
20	Integrated Visual Protection Limited	Partial evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
21	Sylversys	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	14 contacts →
	Indirect evidence “SYLVERSYS is a solutions integration firm with a specialty in providing secure computer and network products/solutions for businesses and organizations in the private and public…” Source: RevenueBase Database · checked Sep 28, 2026
22	Definitive Security Solutions LTD	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	13 contacts →
	Strong evidence “Definitive Security Solutions are an established designer, installer and maintainer of security, CCTV, intruder alarms, access control, power and data, and fire detection systems.” Source: RevenueBase Database · checked Sep 28, 2026
23	Goallsecure	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	13 contacts →
	Indirect evidence “In today’s world, cyber threats are complex and multilayered, so complete protection is not achievable through a single solution or product, that's why GoAllSecure provides a 360°…” Source: RevenueBase Database · checked Sep 28, 2026
24	Bold Communications LTD	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	12 contacts →
	Partial evidence “Bold Communications develops Gemini, an integrated security and safety monitoring platform to maximise efficiency and interoperability in the control room, utilising legacy as…” Source: RevenueBase Database · checked Sep 28, 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: enterprise security system providers. 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 enterprise security system providers.
Partial evidence: Its own public description names part of enterprise security system providers, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name enterprise security system providers. 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 24 of 248 enterprise security system providers based in London, United Kingdom

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Enterprise security system providers based in London, United Kingdom at a glance

As of Sep 28, 2026

25.1%Verified-email coverage

8.3Average contacts per company

1-10Median size (employees)

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

126

11-50

51-200

201-500

501-1,000

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 248 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 enterprise security system providers, 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 “enterprise security system providers”. 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 enterprise security system providers), 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 enterprise security system providers, 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, 515 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 28, 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.

Enterprise security system providers by metro in the United Kingdom

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 enterprise security system providers, 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 enterprise security system providers are there based in London, United Kingdom?

RevenueBase identified 248 enterprise security system providers 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?

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

Which city in the United Kingdom has the most enterprise security system providers?

London leads the United Kingdom with 248 headquartered companies, followed by Manchester (39) and Birmingham (26).

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 515 verified decision-maker contacts tracked across these 248 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 28, 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.