Company lists · Data refreshed September 2026
Top 25 Security monitoring services based in the United Kingdom
RevenueBase identified 1,385 security monitoring services headquartered in the United Kingdom as of September 2026 and tracks 17,856 professional contacts across them, including 6,160 with verified work emails and 1,493 with mobile numbers. London is the largest hub.
This list covers security monitoring services 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.
The 25 largest security monitoring services based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 4,925 | ||||
“Sophos is a cybersecurity leader defending organizations globally with an AI-driven platform and expert-led services.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 2 | 502 | ||||
“SecurityHQ, a global cybersecurity company pioneering Security Performance Engineering for stronger operational performance and resilience.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 3 | 392 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 4 | Marlowe Fire & SecurityPartial evidence | 389 | |||
“Mitie Fire & Security is part of Mitie, the UK’s leading facilities management and professional services company, delivering integrated fire and security solutions that protect…” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 5 | 242 | ||||
“Obrela Security Industries is a global provider of cyber security services.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 6 | 177 | ||||
“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: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 7 | 159 | ||||
“At Cyberfort we are passionate about the cyber security services we deliver for our customers which keeps their people, data, systems and technology infrastructure secure…” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 8 | 137 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 9 | 125 | ||||
“KHIPU Networks is an award winning international Cyber Security Company delivering a wide range of network, wireless and security solutions, technologies and services across…” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 10 | 89 | ||||
“For a better service and competitive price try K4 Security Services At K4 we offer the following: 1.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 11 | 86 | ||||
“CyberGuard Technologies is the security division of Wavenet.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 12 | CybersmartIndirect evidence | 84 | |||
“Cybersecurity should be simple.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 13 | 80 | ||||
“When your business relies on security, compliance and a strong reputation for taking care of your customers, you need a partner that understands your ethos, your challenges and…” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 14 | 80 | ||||
“At Reliance Cyber, we believe in truly partnering with our customers.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 15 | 73 | ||||
“Dionach by Nomios has over 25 years of expertise in information security, supporting organisations in building resilience against ever‑evolving cyber threats.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 16 | 70 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 17 | 69 | ||||
“BauWatch secures your site and assets with rapidly deployed mobile video surveillance systems.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 18 | 68 | ||||
“The organisations that run our world face relentless complexity and evolving threats.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 19 | 66 | ||||
“We help businesses and individuals stay protected in an increasingly complex digital world.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 20 | 66 | ||||
“Welcome to Britsafe Limited Years of Security and Cleaning experience have made us masters in providing defect-free security and cleaning solutions tailor-made to suit the…” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 21 | 64 | ||||
“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, 2026Thanks. The Data Team will review it. | |||||
| 22 | 61 | ||||
“e2e-assure is the UK's leading specialist in Managed Threat Detection and Response through our 24/7/365 UK owned and operated Security Operations Centre (SOC).” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 23 | 61 | ||||
“AlertSystems specialise in the design, installation, service, and maintenance of commercial electronic security and fire safety systems.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
| 24 | WLSPartial evidence | 61 | |||
“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, 2026Thanks. The Data Team will review it. | |||||
| 25 | 58 | ||||
“Black Diamond Security - Safeguarding Your World.” Source: company website · checked Sep 6, 2026Thanks. The Data Team will review it. | |||||
Showing 25 of 1,385 security monitoring services based in the United Kingdom
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Security monitoring services based in the United Kingdom at a glance
As of Sep 6, 2026Companies by employee count
Verified emails by last verification
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 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 services”. 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 services, 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, 6,160 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 monitoring services by metro
- Security monitoring services in London308
- Security monitoring services in Manchester45
Frequently asked
How many security monitoring services are there based in the United Kingdom?
RevenueBase identified 1,385 security monitoring services 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?
Sophos, headquartered in Abingdon, 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 6,160 verified decision-maker contacts tracked across these 1,385 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.
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