Company lists · Data refreshed September 2026

Top 25 Cybersecurity and physical security firms based in the United Kingdom

RevenueBase identified 2,327 company matches for cybersecurity and physical security firms associated with the United Kingdom as of September 2026 and tracks 118,575 professional contacts across them, including 12,354 with verified work emails. London is the largest hub.

This list covers company matches for cybersecurity and physical security firms associated with the United Kingdom, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed September 28, 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 RevenueBase SmartSearch · Exact Recorded Sep 28, 2026 How this list was built
2,327Companies
118,575Contacts tracked
12,354Verified emails
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The 25 largest cybersecurity and physical security firms based in the United Kingdom

Ranked by team size
Top 25 of 2,327 company matches for cybersecurity and physical security firms based in the United Kingdom, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 28, 2026. The RevenueBase SmartSearch column shows Exact match membership in this saved search. Click a contact count to view that company's people. Totals use company locations recorded by RevenueBase; the displayed preview is a smaller selection.
#CompanyRevenueBase SmartSearchHeadquartersEmployeesContacts
1Exact matchLondon, United KingdomHQ recorded Sep 28, 202610001+79,699 contacts →

Exact match

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

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
2Exact matchAbingdon, United KingdomHQ recorded Sep 28, 20265,001-10,0004,925 contacts →

Exact match

“Sophos is a cybersecurity leader defending organizations globally with an AI-driven platform and expert-led services.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
3Exact matchNorthampton, United KingdomHQ recorded Sep 28, 202610001+1,508 contacts →

Exact match

“We are an intelligence-led security business.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
4Exact matchLondon, United KingdomHQ recorded Sep 28, 20261,001-5,000919 contacts →

Exact match

“CIS Security is an independent security company equipped to help customers to solve the complex challenges in today’s digital, connected and regulated business world.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
5Exact matchStaines-upon-thames, United KingdomHQ recorded Sep 28, 2026201-500764 contacts →

Exact match

“MTI provides award-winning, end-to-end technology solutions and services in cyber security and data centre for over 35 years.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
6Exact matchSt Neots, United KingdomHQ recorded Sep 28, 2026201-500640 contacts →

Exact match

“MASS, part of the Cohort plc group, helps you realise the value of your data.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
7Exact matchLondon, United KingdomHQ recorded Sep 28, 2026501-1,000502 contacts →

Exact match

“SecurityHQ, a global cybersecurity company pioneering Security Performance Engineering for stronger operational performance and resilience.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
8Exact matchCirencester, United KingdomHQ recorded Sep 28, 20261,001-5,000422 contacts →

Exact match

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

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
9Exact matchLondon, United KingdomHQ recorded Sep 28, 2026201-500351 contacts →

Exact match

“S-RM is a global intelligence and cyber security consultancy.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
10Exact matchBradford, United KingdomHQ recorded Sep 28, 2026501-1,000326 contacts →

Exact match

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

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
11Exact matchSaffron Walden, United KingdomHQ recorded Sep 28, 20261,001-5,000318 contacts →

Exact match

“Argenbright Security Europe Ltd (ASEL) are a technology led risk management organisation with foundations in data, technology and innovation formed by incorporating two major…”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
12Exact matchReading, United KingdomHQ recorded Sep 28, 2026201-500303 contacts →

Exact match

“Bridewell is the trusted cyber security partner for organisations operating within Critical National Infrastructure (CNI), as well as companies who want the highest standard of…”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
13Exact matchEdinburgh, United KingdomHQ recorded Sep 28, 2026201-500297 contacts →

Exact match

“At Quorum Cyber, we're on a mission to help good people win.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
14Exact matchLeeds, United KingdomHQ recorded Sep 28, 2026201-500260 contacts →

Exact match

“We are a global boutique, specializing exclusively in the convergence of identity-driven security and networking.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
15Exact matchGreenham, United KingdomHQ recorded Sep 28, 2026201-500243 contacts →

Exact match

“Roc Technologies delivers transformational IT solutions to public and private sector organisations across the UK.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
16Exact matchLondon, United KingdomHQ recorded Sep 28, 2026201-500242 contacts →

Exact match

“Obrela Security Industries is a global provider of cyber security services.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
17Exact matchWoking, United KingdomHQ recorded Sep 28, 2026201-500205 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
18Exact matchRomford, United KingdomHQ recorded Sep 28, 2026201-500200 contacts →

Exact match

“OpenView Security Solutions is the UK’S largest privately owned independent security company and provides unique, innovative and technologically excellent solutions to meet…”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
19Exact matchNewcastle Upon Tyne, United KingdomHQ recorded Sep 28, 2026201-500195 contacts →

Exact match

“Surefire Business Protection No matter the sector you work in, or where you’re located in the UK, we can help you to make sure that fire and security problems are not things you…”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
20Exact matchLondon, United KingdomHQ recorded Sep 28, 2026201-500190 contacts →

Exact match

“Intragen is a cyber security business focused on managed Identity solutions and services.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
21Exact matchLondon, United KingdomHQ recorded Sep 28, 202651-200177 contacts →

Exact match

“Whether you’re a business or an individual, digital threats to your precious data and assets can come in any form - external or internal.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
22Exact matchHaslingden, United KingdomHQ recorded Sep 28, 2026201-500170 contacts →

Exact match

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

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
23Exact matchNewcastle Upon Tyne, United KingdomHQ recorded Sep 28, 202651-200168 contacts →

Exact match

“Sapphire delivers comprehensive cyber solutions tailored to your needs, spanning across consultancy, managed services, IT/OT and beyond.”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
24Exact matchMilton Keynes, United KingdomHQ recorded Sep 28, 2026201-500166 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase
25Exact matchAlton, United KingdomHQ recorded Sep 28, 2026201-500165 contacts →

Exact match

“Exclusive Networks is a global trusted cybersecurity specialist for digital infrastructure helping to drive the transition to a totally trusted digital future for all people and…”

Recorded in the RevenueBase company graph · Sep 28, 2026 · View company records in RevenueBase

Showing 25 of 2,327 cybersecurity and physical security firms based in the United Kingdom

See the full list, filter by size, metro and specialty, and access 12,354 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Cybersecurity and physical security firms based in the United Kingdom at a glance

As of Sep 28, 2026
10.4%Verified-email coverage
51.0Average contacts per company
1-10Median size (employees)
30.5%Largest-city concentration · London
Sep 28, 2026Page data refreshed

Companies by employee count

1-10
1,258
11-50
743
51-200
224
201-500
60
501-1,000
16
1,001-5,000
9
5,001-10,000
3
10001+
5

Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 2,327 companies.

How this list was built

The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.

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
Company records associated with the United Kingdom whose business descriptions match “cybersecurity and physical security firms” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
RevenueBase SmartSearch
Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
Public preview
The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
Match quality
RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
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 displayed company carries at least one verified work email. RevenueBase tracks 12,354 professional contacts with verified work emails across the full matched dataset. 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.
Record context
Company records and descriptions can change. Check the company's website for its current services and locations.

Frequently asked

What is RevenueBase SmartSearch?

RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “cybersecurity and physical security firms”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many cybersecurity and physical security firms are there based in the United Kingdom?

RevenueBase identified 2,327 company matches for cybersecurity and physical security firms associated with the United Kingdom as of September 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.

What is the largest company on this list?

G4s tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.

Which city has the most cybersecurity and physical security firms?

London leads with 710 company records, followed by Manchester (74) and Birmingham (44).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 12,354 professional contacts with verified work emails tracked across these 2,327 companies; direct dials are available where recorded.

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 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.