Company lists · Data refreshed September 2026

Top 25 Security monitoring service providers based in the United Kingdom

RevenueBase identified 1,145 security monitoring service providers headquartered in the United Kingdom as of September 2026 and tracks 103,554 professional contacts across them, including 5,523 with verified work emails and 8,590 with mobile numbers. London is the largest hub.

This list covers security monitoring service providers headquartered in the 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, how directly it supports the match, 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 SmartSearch, 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 Match evidence on every row Refreshed Sep 6, 2026 86% judged on-target in blind review
1,145Companies
103,554Contacts tracked
5,523Verified emails
8,590Mobile numbers
Explore all 1,145 companies → Free signup · no credit card · 500 free credits

The 25 largest security monitoring service providers based in the United Kingdom

Ranked by team size
Top 25 of 1,145 security monitoring service providers based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 6, 2026. Evidence rates how directly each company's own description names security monitoring service providers: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#CompanyHeadquartersEmployeesContacts
1
G4sPartial evidence
London, United KingdomHQ checked Sep 6, 202610001+79,699

“G4S is a leading security and facility services company that provides proactive security services and cutting-edge smart technology to deliver tailored, integrated security…”

Source: company website · checked Sep 6, 2026
2
Chubb Fire & SecurityIndirect evidence
Staines, United KingdomHQ checked Sep 6, 202610001+6,169

“Making the world a safer place.”

Source: company website · checked Sep 6, 2026
3
Mitie SecurityPartial evidence
Northampton, United KingdomHQ checked Sep 6, 202610001+1,508

“We are an intelligence-led security business.”

Source: company website · checked Sep 6, 2026
4
Corps SecurityPartial evidence
London, United KingdomHQ checked Sep 6, 20261,001-5,000847

“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: company website · checked Sep 6, 2026
5
Lodge SecurityPartial evidence
Cirencester, United KingdomHQ checked Sep 6, 20261,001-5,000422

“Unlike traditional security providers, we're redefining what protection means in today's world.”

Source: company website · checked Sep 6, 2026
6
Ward SecurityPartial evidence
London, United KingdomHQ checked Sep 6, 20261,001-5,000419

“Ward is an award winning, privately owned business, providing bespoke risk and security solutions including protective security personnel, explosive search dogs, narcotic search…”

Source: company website · checked Sep 6, 2026
7
Ssgc LTDIndirect evidence
Swindon, United KingdomHQ checked Sep 6, 2026501-1,000392

“SSGC is a leading innovator in the Manned Guarding industry, specialising in the application of new technology to improve the performance of its Management team, deployed staff…”

Source: company website · checked Sep 6, 2026
8
Kings Secure TechnologiesIndirect evidence
Bradford, United KingdomHQ checked Sep 6, 2026501-1,000326

“Kings Secure Technologies (KST) is a high-end, enterprise-level systems integrator.”

Source: company website · checked Sep 6, 2026
9Shirley, United KingdomHQ checked Sep 6, 20261,001-5,000226

“MAN Commercial is a leading security company and Training Academy based in Solihull, West Midlands.”

Source: company website · checked Sep 6, 2026
10Woking, United KingdomHQ checked Sep 6, 2026201-500205

“Pilgrims are a global security, risk management and service support company that identifies and manages risks for clients across all sectors, including oil & gas, telecoms…”

Source: company website · checked Sep 6, 2026
11
ADT UK & IrelandIndirect evidence
Sunbury On Thames, United KingdomHQ checked Sep 6, 20261,001-5,000172
Source: company website · checked Sep 6, 2026
12
Texecom LTDIndirect evidence
Haslingden, United KingdomHQ checked Sep 6, 2026201-500170

“Looking after the things people care about, wherever they are’.”

Source: company website · checked Sep 6, 2026
13
The Brooknight GroupPartial evidence
Milton Keynes, United KingdomHQ checked Sep 6, 2026201-500166

“Providing Exceptional Security Services to Corporate and Retail Customers - Brooknight Security, with over 30 years of experience, is the go-to choice for businesses seeking…”

Source: company website · checked Sep 6, 2026
14Sidcup, United KingdomHQ checked Sep 6, 2026201-500166

“Trigion Security Services is the UK provider of Security Guarding and Technical Solutions for Facilicom UK.”

Source: company website · checked Sep 6, 2026
15
The Keyholding CompanyPartial evidence
London, United KingdomHQ checked Sep 6, 202651-200137

“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
16Watford, United KingdomHQ checked Sep 6, 202651-200116

“TSP has a reputation for providing enterprise security solutions, as well as excellent system integration standards and exceptional aftercare support, since its founding in 1988.”

Source: company website · checked Sep 6, 2026
17
K4 Security - K4 GroupPartial evidence
Hounslow, United KingdomHQ checked Sep 6, 2026201-50089

“For a better service and competitive price try K4 Security Services At K4 we offer the following: 1.”

Source: company website · checked Sep 6, 2026
18Whiteley, United KingdomHQ checked Sep 6, 2026501-1,00087

“Croma Security Solutions Group (CSSG) began in 1970 as a family-run business in Shirley, Southampton, known as County Locksmiths.”

Source: company website · checked Sep 6, 2026
19London, United KingdomHQ checked Sep 6, 202651-20085

“At Servoca Secure Solutions, we take great pride in delivering a multi-service security business; offering a range of complementary products and services to both the public and…”

Source: company website · checked Sep 6, 2026
20
Nationwide SecurityPartial evidence
St Albans, United KingdomHQ checked Sep 6, 202651-20081

“Nationwide Security providing both physical and electrical security services throughout the UK.”

Source: company website · checked Sep 6, 2026
21
T3 SecurityPartial evidence
Seaton Burn, United KingdomHQ checked Sep 6, 2026501-1,00080

“T3 Security is a leading National Security Company supplying clients across the UK with bespoke security services.”

Source: company website · checked Sep 6, 2026
22
ABELPartial evidence
Leicester, United KingdomHQ checked Sep 6, 202651-20070

“With over 50 years’ experience in the security industry, Abel has grown to become one of the UK’s largest privately owned providers of electronic security systems.”

Source: company website · checked Sep 6, 2026
23
Bauwatch UK & IrelandIndirect evidence
Northampton, United KingdomHQ checked Sep 6, 202651-20069

“BauWatch secures your site and assets with rapidly deployed mobile video surveillance systems.”

Source: company website · checked Sep 6, 2026
24
Northern Security LTDPartial evidence
Carlisle, United KingdomHQ checked Sep 6, 2026201-50069

“Northern Security Ltd is a leading guarding, alarm response and electronic security business operating throughout the North of England and South West Scotland.”

Source: company website · checked Sep 6, 2026
25
SSS Management ServicesStrong evidence
Bristol, United KingdomHQ checked Sep 6, 202651-20068

“is a security and facilities management business with over 25 years’ experience in monitoring, checking and delivering contractor performance for clients.”

Source: company website · checked Sep 6, 2026

Showing 25 of 1,145 security monitoring service providers based in the United Kingdom

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Security monitoring service providers based in the United Kingdom at a glance

As of Sep 6, 2026
11-50Median size (employees)
LondonLargest hub · 192 HQs
8,590Contacts with mobile numbers
Sep 6, 2026Data refreshed

Companies by employee count

1-10
493
11-50
366
51-200
186
201-500
55
501-1,000
14
1,001-5,000
9
5,001-10,000
1
10001+
3

Verified emails by last verification

0–30
5,195
31–60
303
61–90
2
90–180
1
180+
22

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 service providers, so some rows will be adjacent to the category rather than pure plays. The description and evidence 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 SmartSearch, the natural-language company search available to every RevenueBase user.
What qualifies
Companies headquartered in the United Kingdom whose own description of what they do matches “security monitoring service providers”. Matching reads each company's description, not its industry code or its name.
What we exclude
Companies whose own description does not clearly place them among security monitoring service providers, and records with no verified work email. Companies headquartered outside United Kingdom 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 an evidence 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, 5,523 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.

Frequently asked

How many security monitoring service providers are there based in the United Kingdom?

RevenueBase identified 1,145 security monitoring service providers headquartered in the 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?

G4s, headquartered in London, tops this list with the largest team on record.

Which city has the most security monitoring service providers?

London leads with 192 headquartered companies, followed by Manchester (29) 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 5,523 verified decision-maker contacts tracked across these 1,145 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 SmartSearch, 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.