Company lists · Data refreshed September 2026

Top 24 Security system installation companies based in London, United Kingdom

Name: Security system installation 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 6, 2026 224 companies tracked

RevenueBase identified 224 security system installation companies headquartered in London, United Kingdom as of September 2026 and tracks 1,415 professional contacts across them, including 381 with verified work emails. London is the largest hub.

This list covers security system installation 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 6, 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 6, 2026 86% judged on-target in blind review

224Companies

1,415Contacts tracked

381Verified emails

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The 24 largest security system installation companies based in London, United Kingdom

Ranked by team size

Top 24 of 224 security system installation companies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 6, 2026. RevenueBase Smart Search rates how each company's information relates to security system installation 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	The Keyholding Company	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	137 contacts →
	“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: company website · checked Sep 6, 2026
2	City Security Services Part Of City Group Security	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	201-500	64 contacts →
	“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: company website · checked Sep 6, 2026
3	WLS	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	61 contacts →
	“WLS (West London Security) has been providing security and solutions to London's homes and businesses for over 40 years.” Source: company website · checked Sep 6, 2026
4	Custom Intelligent Security	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	51 contacts →
	“Established in Custom Intelligent Security is a technology driven ISO27001 & NSi Gold Accredited independent electronic security specialist with a proven track record of…” Source: company website · checked Sep 6, 2026
5	Sensetech Systems LTD	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	50 contacts →
	“Sensetech Systems Ltd is an LPS1014 Accredited independent Fire Alarm, Security and Structured Data Cabling Company.” Source: company website · checked Sep 6, 2026
6	Ak9 Security And FM Solutions LTD	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	501-1,000	43 contacts →
	“AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.” Source: company website · checked Sep 6, 2026
7	SMC Smart Homes	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	41 contacts →
	“SMC are a leading custom electronic system design, installation and aftercare company.” Source: company website · checked Sep 6, 2026
8	Gratte Brothers Security Systems & Software	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	39 contacts →
	“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: company website · checked Sep 6, 2026
9	Universal Security Systems LTD	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	39 contacts →
	“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: company website · checked Sep 6, 2026
10	Pafi LTD	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	32 contacts →
	“Pafi Ltd, Was formed in 1995 to design, install and maintain integrated security solutions for the commercial market.” Source: company website · checked Sep 6, 2026
11	DS Security Group LTD	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	11-50	27 contacts →
	“CCTV and Access Control Service and installation specialists Established in 1993 DS Security prides itself on customer service.” Source: company website · checked Sep 6, 2026
12	Welcome Gate	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	23 contacts →
	“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: company website · checked Sep 6, 2026
13	Dennis Johns Service Group	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	20 contacts →
	“The Dennis Johns Service Group is a forward thinking group of companies providing, Electrical, CCTV and Access Control, installation and maintenance contracting services.” Source: company website · checked Sep 6, 2026
14	Integrated Visual Protection Limited	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	16 contacts →
	“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: company website · checked Sep 6, 2026
15	Definitive Security Solutions LTD	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	11-50	13 contacts →
	“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: company website · checked Sep 6, 2026
16	Square Mile Fire & Security	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	11-50	13 contacts →
	“We are an independent business specialising in the delivery of fire systems, as well as a comprehensive range of security systems.” Source: company website · checked Sep 6, 2026
17	OPEM	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	11-50	13 contacts →
	“We design, install and maintain CCTV and access control systems across a variety of commercial office sectors including coworking, serviced offices and traditional office design.” Source: company website · checked Sep 6, 2026
18	Securico Fire & Security	Indirect evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	12 contacts →
	Source: company website · checked Sep 6, 2026
19	The Security Group	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	51-200	11 contacts →
	“The Security Group delivers state-of-the-art security solutions to protect businesses, assets, and people.” Source: company website · checked Sep 6, 2026
20	Reltech Solutions Limited	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	11-50	11 contacts →
	“RELTECH SOLUTIONS LIMITED is an Electronic Fire and Security company that provide design, installation and maintenance services on all aspects of security and life safety systems.” Source: company website · checked Sep 6, 2026
21	Guarding Professionals LTD	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	1-10	10 contacts →
	“Guarding Professionals is a customer focused security services company providing cost effective advanced security solutions using technical excellence and superior customer…” Source: company website · checked Sep 6, 2026
22	LDN Security Solutions Limited	Strong evidence	London, United KingdomHQ checked Sep 6, 2026	1-10	10 contacts →
	“London-based security company specialising in the design, installation, service and maintenance of single domestic, multi-occupancy residential and commercial security systems.” Source: company website · checked Sep 6, 2026
23	Delta Security 1962 LTD	Indirect evidence	London, United KingdomHQ checked Sep 6, 2026	11-50	8 contacts →
	“Our goal is so simple we can sum it up in one word - quality.” Source: company website · checked Sep 6, 2026
24	Pacific Business Solutions LTD	Partial evidence	London, United KingdomHQ checked Sep 6, 2026	11-50	8 contacts →
	“We take your security seriously and ensure that you and your property are safe and in secure hands.” Source: company website · checked Sep 6, 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 system installation 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 system installation companies.
Partial evidence: Its own public description names part of security system installation companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name security system installation 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 24 of 224 security system installation companies based in London, United Kingdom

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Security system installation companies based in London, United Kingdom at a glance

As of Sep 6, 2026

26.9%Verified-email coverage

6.3Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · London

Sep 6, 2026Page data refreshed

Companies by employee count

1-10

132

11-50

51-200

201-500

501-1,000

Email recency for this list is measured across the whole United Kingdom list rather than this city, so it is reported there. Company counts and contact totals on this page are exact for London, over 224 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 system installation 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 system installation 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 system installation 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 system installation 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, 381 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 6, 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 system installation companies by metro in the United Kingdom

Security system installation companies in London224
Security system installation companies in Manchester43
Security system installation companies in Birmingham34
Security system installation companies in Glasgow28

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 system installation 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 system installation companies are there based in London, United Kingdom?

RevenueBase identified 224 security system installation 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?

The Keyholding Company, headquartered in London, tops this list with the largest team on record.

Which city has the most security system installation companies?

London leads with 224 headquartered companies, followed by Manchester (43) and Birmingham (34).

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 381 verified decision-maker contacts tracked across these 224 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 6, 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.