Company lists · Data refreshed September 2026

Top 24 Alarm system companies based in London, United Kingdom

Name: Alarm system 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 19, 2026 167 companies tracked

RevenueBase identified 167 alarm system companies headquartered in London, United Kingdom as of September 2026 and tracks 910 professional contacts across them, including 227 with verified work emails. London is the largest hub.

This list covers alarm system 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 19, 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 19, 2026 86% judged on-target in blind review

167Companies

910Contacts tracked

227Verified emails

Explore this list → Free signup · no credit card · 500 free credits

The 24 largest alarm system companies based in London, United Kingdom

Ranked by team size

Top 24 of 167 alarm system companies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 19, 2026. RevenueBase Smart Search rates how each company's information relates to alarm system 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	City Security Services Part Of City Group Security	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	201-500	64 contacts →
	Indirect 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 19, 2026
2	WLS	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	61 contacts →
	Indirect 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 19, 2026
3	Custom Intelligent Security	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	51 contacts →
	Indirect 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 19, 2026
4	Sensetech Systems LTD	Strong evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	50 contacts →
	Strong evidence “Sensetech Systems Ltd is an LPS1014 Accredited independent Fire Alarm, Security and Structured Data Cabling Company.” Source: RevenueBase Database · checked Sep 19, 2026
5	Universal Security Systems LTD	Partial evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	39 contacts →
	Partial 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 19, 2026
6	Pafi LTD	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	32 contacts →
	Indirect evidence “Pafi Ltd, Was formed in 1995 to design, install and maintain integrated security solutions for the commercial market.” Source: RevenueBase Database · checked Sep 19, 2026
7	Integrated Visual Protection Limited	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	16 contacts →
	Indirect 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 19, 2026
8	Definitive Security Solutions LTD	Strong evidence	London, United KingdomHQ checked Sep 19, 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 19, 2026
9	Square Mile Fire & Security	Partial evidence	London, United KingdomHQ checked Sep 19, 2026	11-50	13 contacts →
	Partial evidence “We are an independent business specialising in the delivery of fire systems, as well as a comprehensive range of security systems.” Source: RevenueBase Database · checked Sep 19, 2026
10	Securico Fire & Security	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	12 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 19, 2026
11	The Security Group	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	51-200	11 contacts →
	Indirect evidence “The Security Group delivers state-of-the-art security solutions to protect businesses, assets, and people.” Source: RevenueBase Database · checked Sep 19, 2026
12	Reltech Solutions Limited	Partial evidence	London, United KingdomHQ checked Sep 19, 2026	11-50	11 contacts →
	Partial evidence “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: RevenueBase Database · checked Sep 19, 2026
13	LDN Security Solutions Limited	Partial evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	10 contacts →
	Partial evidence “London-based security company specialising in the design, installation, service and maintenance of single domestic, multi-occupancy residential and commercial security systems.” Source: RevenueBase Database · checked Sep 19, 2026
14	Fire Plus Security	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	11-50	10 contacts →
	Indirect evidence “At Fire Plus Security we are proud to deliver tailored Fire & Security solutions to residential, commercial and public sector organisations throughout the UK & Europe.” Source: RevenueBase Database · checked Sep 19, 2026
15	Delta Security 1962 LTD	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	11-50	8 contacts →
	Indirect evidence “Our goal is so simple we can sum it up in one word - quality.” Source: RevenueBase Database · checked Sep 19, 2026
16	NES Security Limited	Partial evidence	London, United KingdomHQ checked Sep 19, 2026	11-50	7 contacts →
	Partial evidence “An independent electrical services company providing bespoke and high-quality CCTV, Security, Access control and Automation technology systems to private and corporate clients in…” Source: RevenueBase Database · checked Sep 19, 2026
17	Security Installation Services LTD	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	7 contacts →
	Indirect evidence “Security Installation Services Ltd provide a fast and efficient security service across Greater London and North Kent that includes the installation and maintenance of a wide…” Source: RevenueBase Database · checked Sep 19, 2026
18	Astoria Fire And Security	Partial evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	5 contacts →
	Partial evidence “Astoria Fire and Security carry out installations and provide maintenance services in the Electrical, Fire Alarm and CCTV industry to commercial, industrial and domestic…” Source: RevenueBase Database · checked Sep 19, 2026
19	Controlled LTD	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	4 contacts →
	Indirect evidence “is a leading provider of integrated network security and fire detection solutions.” Source: RevenueBase Database · checked Sep 19, 2026
20	Dram Fire & Security	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	4 contacts →
	Indirect evidence “We are one of London’s leading providers of high-quality security and fire detection solutions, DRAM Fire & Security was founded in 2009, and carries a wealth of knowledge and…” Source: RevenueBase Database · checked Sep 19, 2026
21	Ge4orce Fire & Security Solutions	Strong evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	4 contacts →
	Strong evidence “We provide CCTV, alarm systems, access control and fire safety solutions for residential and commercial properties across London.” Source: RevenueBase Database · checked Sep 19, 2026
22	Balthorne Security Solutions LTD	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	11-50	4 contacts →
	Indirect evidence “At Balthorne Security Solutions, we understand the risks people face and the importance of reliable security.” Source: RevenueBase Database · checked Sep 19, 2026
23	Prime Fire & Security	Partial evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	4 contacts →
	Partial evidence “We provide a comprehensive range of services in Intruder Alarms, Fire Alarms, CCTV, Access Control and much more!” Source: RevenueBase Database · checked Sep 19, 2026
24	Aegis Security Solutions	Indirect evidence	London, United KingdomHQ checked Sep 19, 2026	1-10	4 contacts →
	Indirect evidence “At Aegis, we do things differently.” Source: RevenueBase Database · checked Sep 19, 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: alarm system 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 alarm system companies.
Partial evidence: Its own public description names part of alarm system companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name alarm system 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 167 alarm system companies based in London, United Kingdom

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 227 reachable decision-makers.

Free signup · no credit card

View the full list →

Alarm system companies based in London, United Kingdom at a glance

As of Sep 19, 2026

24.9%Verified-email coverage

5.4Average contacts per company

1-10Median size (employees)

100.0%Largest-city concentration · London

Sep 19, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

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 167 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 alarm system 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 “alarm system 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 alarm system 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 alarm system 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, 227 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 19, 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.

Alarm system companies 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 alarm system 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 alarm system companies are there based in London, United Kingdom?

RevenueBase identified 167 alarm system 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?

City Security Services Part Of City Group Security, headquartered in London, tops this list with the largest team on record.

Which city has the most alarm system companies?

London leads with 167 headquartered companies, followed by Manchester (43) and Glasgow (27).

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 227 verified decision-maker contacts tracked across these 167 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 19, 2026.

Ready to reach these companies? Verified emails and direct dials for all 167 alarm system companies based in London, United Kingdom. Start with a free account, no credit card.

Download this list →

Related lists

Alarm system companies by geography

Browse the directory

Browse: Companies home · Alarm system companies in United Kingdom · All United Kingdom lists · All Alarm system companies lists · New lists

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.