Company lists · Data refreshed September 2026

Top 25 Critical infrastructure security companies based in the United Kingdom

RevenueBase identified 894 company matches for critical infrastructure security companies associated with the United Kingdom as of September 2026 and tracks 17,828 professional contacts across them, including 3,769 with verified work emails. London is the largest hub.

This list covers company matches for critical infrastructure security companies 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 27, 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 27, 2026 How this list was built
894Companies
17,828Contacts tracked
3,769Verified emails
Explore this list → Free signup · no credit card · 500 free credits

The 25 largest critical infrastructure security companies based in the United Kingdom

Ranked by team size
Top 25 of 894 company matches for critical infrastructure security companies based in the United Kingdom, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Sep 27, 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 27, 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 27, 2026 · View company records in RevenueBase
2Exact matchLondon, United KingdomHQ recorded Sep 27, 20261,001-5,000597 contacts →

Exact match

“Part of ICTS Europe Group, ICTS UK & Ireland is a professional services firm which has been specialised in security risk for the past 39+ years.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
3Exact matchLondon, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
4Exact matchCirencester, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
5Exact matchReading, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
6Exact matchLondon, United KingdomHQ recorded Sep 27, 2026201-500242 contacts →

Exact match

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

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
7Exact matchWoking, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
8Exact matchRomford, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
9Exact matchLeeds, United KingdomHQ recorded Sep 27, 20261,001-5,000180 contacts →

Exact match

“Established in 1978, Bridgegate Security is proud to be one of the UK’s largest independent security contractors.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
10Exact matchNewcastle Upon Tyne, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
11Exact matchEnfield, United KingdomHQ recorded Sep 27, 2026501-1,000166 contacts →

Exact match

“We are GUK.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
12Exact matchMilton Keynes, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
13Exact matchAlton, United KingdomHQ recorded Sep 27, 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 27, 2026 · View company records in RevenueBase
14Exact matchSheffield, United KingdomHQ recorded Sep 27, 2026201-500165 contacts →

Exact match

“Ovarro's technology is used throughout the world to monitor, control and manage critical and national infrastructure.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
15Exact matchThatcham, United KingdomHQ recorded Sep 27, 202651-200159 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
16Exact matchLondon, United KingdomHQ recorded Sep 27, 202651-200137 contacts →

Exact match

“The Keyholding Company are a tech-enabled mobile security services company, specialising in alarm response, mobile patrols, locks and unlocks, emergency and temporary guarding…”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
17Exact matchPortsmouth, United KingdomHQ recorded Sep 27, 2026201-500127 contacts →

Exact match

“Vespasian Security was formed in February 2006.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
18Exact matchFleet, United KingdomHQ recorded Sep 27, 202651-200125 contacts →

Exact match

“KHIPU Networks is an award winning international Cyber Security Company delivering a wide range of network, wireless and security solutions, technologies and services across…”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
19Exact matchPoole, United KingdomHQ recorded Sep 27, 2026201-500115 contacts →

Exact match

“Solace Global Risk began in 2010 with a simple belief: when people face risk, they need partners who act quickly and stand by their word.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
20Exact matchCastle Donington, United KingdomHQ recorded Sep 27, 2026501-1,000106 contacts →

Exact match

“Protecting People, Property, Assets & Brands.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
21Exact matchLondon, United KingdomHQ recorded Sep 27, 202651-200105 contacts →

Exact match

“Cybersecurity specialists providing technology and telecoms solutions that gives you the leadership, experience and resilience you need to build and secure the future of work.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
22Exact matchRoyal Leamington Spa, United KingdomHQ recorded Sep 27, 2026201-50095 contacts →

Exact match

“Optilan is a leading independent security and communications systems integrator worldwide.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
23Exact matchGlasgow, United KingdomHQ recorded Sep 27, 202651-20093 contacts →

Exact match

“Innovation is at our core.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
24Exact matchBingham, United KingdomHQ recorded Sep 27, 2026201-50091 contacts →

Exact match

“Octavian Security is part of the Octavian Group, a global leader delivering integrated solutions across security, facilities management, and technology-led services.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase
25Exact matchLondon, United KingdomHQ recorded Sep 27, 202651-20087 contacts →

Exact match

“ITC Secure is an advisory-led cyber security services company.”

Recorded in the RevenueBase company graph · Sep 27, 2026 · View company records in RevenueBase

Showing 25 of 894 critical infrastructure security companies based in the United Kingdom

See the full list, filter by size, metro and specialty, and access 3,769 tracked professional contacts with verified work emails. Direct dials are available where recorded.

Free signup · no credit card

View the full list →

Critical infrastructure security companies based in the United Kingdom at a glance

As of Sep 27, 2026
21.1%Verified-email coverage
19.9Average contacts per company
11-50Median size (employees)
34.0%Largest-city concentration · London
Sep 27, 2026Page data refreshed

Companies by employee count

1-10
390
11-50
265
51-200
162
201-500
50
501-1,000
15
1,001-5,000
6
5,001-10,000
1
10001+
1

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 894 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 “critical infrastructure security companies” 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 3,769 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 27, 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.

Critical infrastructure security companies by metro

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 “critical infrastructure security companies”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many critical infrastructure security companies are there based in the United Kingdom?

RevenueBase identified 894 company matches for critical infrastructure security companies 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?

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

Which city has the most critical infrastructure security companies?

London leads with 304 company records, followed by Manchester (26) and Birmingham (24).

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 3,769 professional contacts with verified work emails tracked across these 894 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 27, 2026.

Ready to reach these companies? Verified emails and direct dials for all 894 critical infrastructure security companies based in the United Kingdom. Start with a free account, no credit card.

Download this list →

Related 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 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.