Company lists · Data refreshed September 2026

Top 25 Critical infrastructure security integrators based in the United Kingdom

RevenueBase identified 682 critical infrastructure security integrators headquartered in the United Kingdom as of September 2026 and tracks 10,148 professional contacts across them, including 3,992 with verified work emails. London is the largest hub.

This list covers critical infrastructure security integrators 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, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 27, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, 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 RevenueBase Smart Search rating on every row Refreshed Sep 27, 2026 86% judged on-target in blind review
682Companies
10,148Contacts tracked
3,992Verified emails
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The 25 largest critical infrastructure security integrators based in the United Kingdom

Ranked by team size
Top 25 of 682 critical infrastructure security integrators based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 27, 2026. RevenueBase Smart Search rates how each company's information relates to critical infrastructure security integrators: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceLondon, United KingdomHQ checked Sep 27, 2026501-1,000502 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
2Indirect evidenceExeter, United KingdomHQ checked Sep 27, 2026501-1,000386 contacts →

Indirect evidence

“Trinity’s mission statement is simple - to provide high quality design, installation, commissioning and long term after care of Fire Detection, Fire Suppression, Life Safety and…”

Source: RevenueBase Database · checked Sep 27, 2026
3Partial evidenceBradford, United KingdomHQ checked Sep 27, 2026501-1,000326 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
4Strong evidenceReading, United KingdomHQ checked Sep 27, 2026201-500303 contacts →

Strong evidence

“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…”

Source: RevenueBase Database · checked Sep 27, 2026
5Strong evidenceMarlow, United KingdomHQ checked Sep 27, 2026201-500200 contacts →

Strong evidence

“Founded in 1996 we have grown into one of the UK and Ireland’s leading qualified and accredited security and fire systems integrators, working across Europe to bring together…”

Source: RevenueBase Database · checked Sep 27, 2026
6Partial evidenceRomford, United KingdomHQ checked Sep 27, 2026201-500200 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
7Indirect evidenceHaslingden, United KingdomHQ checked Sep 27, 2026201-500170 contacts →

Indirect evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
8Partial evidenceAlton, United KingdomHQ checked Sep 27, 2026201-500165 contacts →

Partial evidence

“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…”

Source: RevenueBase Database · checked Sep 27, 2026
9Strong evidenceSheffield, United KingdomHQ checked Sep 27, 2026201-500165 contacts →

Strong evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
10Partial evidenceLondon, United KingdomHQ checked Sep 27, 202651-200159 contacts →

Partial evidence

“QCIC is an award-winning global engineering firm specialising in designing, building and running security systems.”

Source: RevenueBase Database · checked Sep 27, 2026
11Partial evidenceLeeds, United KingdomHQ checked Sep 27, 202651-200157 contacts →

Partial evidence

“A premier provider of security products and services across England, Gough & Kelly was formed in 1988 to influence and inspire the security and electrical marketplace by providing…”

Source: RevenueBase Database · checked Sep 27, 2026
12Strong evidenceGlasgow, United KingdomHQ checked Sep 27, 202651-200153 contacts →

Strong evidence

“Pointer Limited We are a Specialist Fire and Security Services Integrator.”

Source: RevenueBase Database · checked Sep 27, 2026
13Strong evidenceChalfont St Peter, United KingdomHQ checked Sep 27, 202651-200145 contacts →

Strong evidence

“Frontline Security Solutions is a global electronic security integrator specialising in Access Control, CCTV, Intruder and Intercom systems that protect people, property and…”

Source: RevenueBase Database · checked Sep 27, 2026
14Partial evidenceFleet, United KingdomHQ checked Sep 27, 202651-200125 contacts →

Partial evidence

“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: RevenueBase Database · checked Sep 27, 2026
15Strong evidenceEynsham, United KingdomHQ checked Sep 27, 202651-200117 contacts →

Strong evidence

“European Electronique is a leading UK systems Integrator, specialising in the delivery of secure technology platforms including Hybrid IT, Cyber Security and Networking…”

Source: RevenueBase Database · checked Sep 27, 2026
16Partial evidenceWatford, United KingdomHQ checked Sep 27, 202651-200116 contacts →

Partial evidence

“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: RevenueBase Database · checked Sep 27, 2026
17Partial evidenceLondon, United KingdomHQ checked Sep 27, 2026201-50097 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
18Strong evidenceRoyal Leamington Spa, United KingdomHQ checked Sep 27, 2026201-50095 contacts →

Strong evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
19Indirect evidenceMansfield, United KingdomHQ checked Sep 27, 202651-20094 contacts →

Indirect evidence

“Better protect your people, places and spaces.”

Source: RevenueBase Database · checked Sep 27, 2026
20Partial evidenceWhiteley, United KingdomHQ checked Sep 27, 2026501-1,00087 contacts →

Partial evidence

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

Source: RevenueBase Database · checked Sep 27, 2026
21Partial evidenceChertsey, United KingdomHQ checked Sep 27, 2026201-50087 contacts →

Partial evidence

“Scutum Fire & Security Ltd.”

Source: RevenueBase Database · checked Sep 27, 2026
22Strong evidenceCamberley, United KingdomHQ checked Sep 27, 202651-20079 contacts →

Strong evidence

“Control Center is trusted by the best-informed security operations around the world to provide proactive physical security management for mission-critical command and control.”

Source: RevenueBase Database · checked Sep 27, 2026
23Indirect evidenceBristol, United KingdomHQ checked Sep 27, 202651-20075 contacts →

Indirect evidence

“Synoptix was formed in 2011 to provide engineering solutions across various technical industries.”

Source: RevenueBase Database · checked Sep 27, 2026
24Strong evidenceMatfen, United KingdomHQ checked Sep 27, 202651-20071 contacts →

Strong evidence

“RHI Industrials provide Physical and Electronic Security Solutions to the UK's major utility companies and partners: Critical National Infrastructure Facilities, Electricity…”

Source: RevenueBase Database · checked Sep 27, 2026
25Indirect evidencePortsmouth, United KingdomHQ checked Sep 27, 202651-20067 contacts →

Indirect evidence

“McAndrew Martin Ltd is a specialist provider of integrated design, engineering and construction services, delivering secure solutions to foster a safer, more resilient world.”

Source: RevenueBase Database · checked Sep 27, 2026

Showing 25 of 682 critical infrastructure security integrators based in the United Kingdom

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

As of Sep 27, 2026
39.3%Verified-email coverage
14.9Average contacts per company
11-50Median size (employees)
19.4%Largest-city concentration · London
Sep 27, 2026Page data refreshed

Companies by employee count

1-10
320
11-50
236
51-200
90
201-500
22
501-1,000
9
1,001-5,000
4

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 682 companies.

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 critical infrastructure security integrators, so some rows will be adjacent to the category rather than pure plays. The description and RevenueBase Smart Search 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 Smart Search, 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 “critical infrastructure security integrators”. Matching reads each company's description, not its industry code or its name.
RevenueBase Smart Search
RevenueBase Smart Search is how this list is assembled and how each row is rated. RevenueBase's data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to a category defined in a user's own words. Each row is rated strong evidence (its own description names critical infrastructure security integrators), partial evidence (it names part of the category) or indirect evidence (the description shown names none of it and the match rests on the rest of the company's profile). The description supporting each rating is quoted on the row.
What we exclude
Companies whose own description does not clearly place them among critical infrastructure security integrators, 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 its RevenueBase Smart Search 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, 3,992 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 27, 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.

Critical infrastructure security integrators by metro

Frequently asked

What is RevenueBase Smart Search?

RevenueBase Smart Search is how RevenueBase decides which companies belong on this list and how strongly each one fits. Its data engine and AI assess a company's LinkedIn profile, information supplied directly by the company, its website and other publicly available information, then relate it to the category the list is about. Each row is rated strong evidence when the company's own description names critical infrastructure security integrators, partial evidence when it names part of the category, and indirect evidence when the description shown names none of it and the match rests on the rest of the company's profile.

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

RevenueBase identified 682 critical infrastructure security integrators 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?

Securityhq, headquartered in Gb, tops this list with the largest team on record.

Which city has the most critical infrastructure security integrators?

London leads with 132 headquartered companies, followed by Manchester (14) and Birmingham (10).

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 3,992 verified decision-maker contacts tracked across these 682 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 27, 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 Smart Search, 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.