Company lists · Data refreshed November 2026

Top 20 Critical infrastructure security services based in London, United Kingdom

RevenueBase identified 501 company matches for critical infrastructure security services associated with London, United Kingdom as of November 2026 and tracks 8,716 professional contacts across them, including 1,488 with verified work emails. Across the United Kingdom, London is the largest hub for this category.

This list covers company matches for critical infrastructure security services associated with London, 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 November 5, 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 Nov 5, 2026 How this list was built
501Companies
8,716Contacts tracked
1,488Verified emails
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The 20 largest critical infrastructure security services based in London, United Kingdom

Ranked by team size
Top 20 of 501 company matches for critical infrastructure security services based in London, United Kingdom, ordered by professional contacts tracked in RevenueBase, largest first. Recorded Nov 5, 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 Nov 5, 20261,001-5,0001,029 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 · Nov 5, 2026 · View company records in RevenueBase
2Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-200165 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 · Nov 5, 2026 · View company records in RevenueBase
3Exact matchLondon, United KingdomHQ recorded Nov 5, 202611-50127 contacts →

Exact match

“At Secon, we empower our clients to reach their full potential by taking the stress out of cyber security.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
4Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-200125 contacts →

Exact match

“We are TRPGLOBAL, your strategic partner in helping you with the complexities of risk management.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
5Exact matchLondon, United KingdomHQ recorded Nov 5, 2026201-500104 contacts →

Exact match

“As an independent IT security specialist, Caretower provide comprehensive solutions to individual problems, thus allowing our recommendations to be unbiased.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
6Exact matchLondon, United KingdomHQ recorded Nov 5, 202611-5095 contacts →

Exact match

“We are proud of our unique track record.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
7Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20095 contacts →

Exact match

“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…”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
8Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20086 contacts →

Exact match

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

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
9Exact matchLondon, United KingdomHQ recorded Nov 5, 202611-5083 contacts →

Exact match

“Assist Security Group (ASG) helps clients build resilient, comprehensive security strategies that protect their people and assets, business continuity and reputation.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
10Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20074 contacts →

Exact match

“Saladin is a security services and risk management company, operating mainly in complex and unstable regions of the world.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
11Exact matchLondon, United KingdomHQ recorded Nov 5, 2026201-50067 contacts →

Exact match

“Black Diamond Security - Safeguarding Your World.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
12Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20066 contacts →

Exact match

“Cyro Cyber are your cyber security Guardians.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
13Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20063 contacts →

Exact match

“CyberOwl helps asset operators in the maritime and critical national infrastructure sectors gain visibility, cyber security and cyber compliance of systems on their distributed…”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
14Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20063 contacts →

Exact match

“At Hexegic we are not just passionate about protecting data through our Cyber services we are passionate about helping companies release the potential of the data they hold…”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
15Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20053 contacts →

Exact match

“In today’s complex threat environment, businesses, individuals, and organisations require trusted partners to provide the ultimate assurance that their assets are well protected.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
16Exact matchLondon, United KingdomHQ recorded Nov 5, 2026501-1,00050 contacts →

Exact match

“AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
17Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20050 contacts →

Exact match

“Electranet’s mission is to be a preferred partner to the public and private sectors, bringing competitively priced, secure and innovative solutions to the market.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
18Exact matchLondon, United KingdomHQ recorded Nov 5, 202611-5048 contacts →

Exact match

“GSA Global is a specialist security, investigations and risk management consultancy helping organisations, families and individuals respond to serious, complex and emerging…”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
19Exact matchLondon, United KingdomHQ recorded Nov 5, 202611-5044 contacts →

Exact match

“SECFORCE are vendor independent offensive security specialists providing effective business risk intelligence and strategic security consulting.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase
20Exact matchLondon, United KingdomHQ recorded Nov 5, 202651-20043 contacts →

Exact match

“CornerStone is an award winning, independent, security and digital building consulting firm with headquarters in the UK.”

Recorded in the RevenueBase company graph · Nov 5, 2026 · View company records in RevenueBase

Showing 20 of 501 critical infrastructure security services based in London, United Kingdom

See the full list, filter by size, metro and specialty, and access 1,488 tracked professional contacts with verified work emails. Direct dials are available where recorded.

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Critical infrastructure security services based in London, United Kingdom at a glance

As of Nov 5, 2026
17.1%Verified-email coverage
17.4Average contacts per company
11-50Median size (employees)
Nov 5, 2026Page data refreshed

Companies by employee count

1-10
213
11-50
160
51-200
94
201-500
19
501-1,000
8
1,001-5,000
4
10001+
1

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 501 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 London, United Kingdom whose business descriptions match “critical infrastructure security services” 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 1,488 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 November 5, 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 services by metro in the United Kingdom

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 services”; each Exact match badge shows search membership, not an individual similarity or quality score.

How many critical infrastructure security services are there based in London, United Kingdom?

RevenueBase identified 501 company matches for critical infrastructure security services associated with London, United Kingdom as of November 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 in the United Kingdom has the most critical infrastructure security services?

London leads the United Kingdom with 501 company records, followed by Manchester (42) and Birmingham (39).

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 1,488 professional contacts with verified work emails tracked across these 501 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 November 5, 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.