Company lists · Data refreshed September 2026

Top 25 Cloud security testing services based in the United Kingdom

RevenueBase identified 213 cloud security testing services headquartered in the United Kingdom as of September 2026 and tracks 2,621 professional contacts across them, including 585 with verified work emails. London is the largest hub.

This list covers cloud security testing 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, 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
213Companies
2,621Contacts tracked
585Verified emails
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The 25 largest cloud security testing services based in the United Kingdom

Ranked by team size
Top 25 of 213 cloud security testing services 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 cloud security testing services: 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 evidenceThatcham, United KingdomHQ checked Sep 27, 202651-200159 contacts →

Partial evidence

“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: RevenueBase Database · checked Sep 27, 2026
2Strong evidenceLeeds, United KingdomHQ checked Sep 27, 202651-20099 contacts →

Strong evidence

“AppCheck is a Complete Enterprise Security Testing Solution that provides up to the minute vulnerability coverage for your entire estate.”

Source: RevenueBase Database · checked Sep 27, 2026
3Partial evidenceOxford, United KingdomHQ checked Sep 27, 202651-20073 contacts →

Partial evidence

“Dionach by Nomios has over 25 years of expertise in information security, supporting organisations in building resilience against ever‑evolving cyber threats.”

Source: RevenueBase Database · checked Sep 27, 2026
4Indirect evidenceManchester, United KingdomHQ checked Sep 27, 202611-5036 contacts →

Indirect evidence

“Secarma exists to keep the world safe.”

Source: RevenueBase Database · checked Sep 27, 2026
5Indirect evidenceCambridge, United KingdomHQ checked Sep 27, 202611-5034 contacts →

Indirect evidence

“Pentesting Exams by Pentesting Experts.”

Source: RevenueBase Database · checked Sep 27, 2026
6Partial evidenceBirmingham, United KingdomHQ checked Sep 27, 202611-5032 contacts →

Partial evidence

“Aristi is a specialist provider of cyber security services with over 17 years of experience.”

Source: RevenueBase Database · checked Sep 27, 2026
7Partial evidenceSolihull, United KingdomHQ checked Sep 27, 202611-5031 contacts →

Partial evidence

“SPECIALISTS IN IT SECURITY AND COMPLIANCE Our goal is to help customers define, develop and implement information security and compliance services, no matter what stage of the…”

Source: RevenueBase Database · checked Sep 27, 2026
8Indirect evidencePortsmouth, United KingdomHQ checked Sep 27, 202611-5029 contacts →

Indirect evidence

“Imagine a world where cyber threats are simply another challenge that you're fully equipped to handle.”

Source: RevenueBase Database · checked Sep 27, 2026
9Partial evidenceAltrincham, United KingdomHQ checked Sep 27, 202611-5026 contacts →

Partial evidence

“Based in Manchester UK, we are an independent Cyber Security Consultancy providing Security services across a wide range of markets, from multi-national Corporate Organisations…”

Source: RevenueBase Database · checked Sep 27, 2026
10Partial evidenceLondon, United KingdomHQ checked Sep 27, 202651-20024 contacts →

Partial evidence

“SSL247 (A Sectigo Company) has nearly 20 years of security consulting experience operating in 18 different markets globally.”

Source: RevenueBase Database · checked Sep 27, 2026
11Strong evidenceNewbury, United KingdomHQ checked Sep 27, 202611-5023 contacts →

Strong evidence

“CyberCrowd are a market leader in the cyber security realm, offering everything from Assessment Services through to Pen Testing, CISOaaS, Certification Readiness, DPO services…”

Source: RevenueBase Database · checked Sep 27, 2026
12Indirect evidenceLondon, United KingdomHQ checked Sep 27, 202611-5023 contacts →

Indirect evidence

“Toro was founded on creating the UK's first Red Team penetration test - and then attacking hundreds of clients by hacking their systems, influencing / social engineering staff and…”

Source: RevenueBase Database · checked Sep 27, 2026
13Partial evidenceCambridge, United KingdomHQ checked Sep 27, 202611-5021 contacts →

Partial evidence

“Chaleit is a cyber security management consultancy that aligns business context with real-world capability to solve complex risks.”

Source: RevenueBase Database · checked Sep 27, 2026
14Partial evidenceTunbridge Wells, United KingdomHQ checked Sep 27, 202611-5019 contacts →

Partial evidence

“Razorthorn Security is a specialist cybersecurity consultancy founded in 2007, with nearly two decades of experience helping organisations protect their data, their systems and…”

Source: RevenueBase Database · checked Sep 27, 2026
15Indirect evidenceLeeds, United KingdomHQ checked Sep 27, 202611-5019 contacts →

Indirect evidence

“Halo I.S is not just another cybersecurity organization based in the UK; we're a testament to evolution and client-centric innovation.”

Source: RevenueBase Database · checked Sep 27, 2026
16Partial evidenceLondon, United KingdomHQ checked Sep 27, 202611-5018 contacts →

Partial evidence

“th4ts3cur1ty.company supplies cyber security services internationally.”

Source: RevenueBase Database · checked Sep 27, 2026
17Strong evidenceChelmsford, United KingdomHQ checked Sep 27, 2026201-50018 contacts →

Strong evidence

“Organisation focused on Cloud and Security”

Source: RevenueBase Database · checked Sep 27, 2026
18Indirect evidenceLondon, United KingdomHQ checked Sep 27, 202611-5017 contacts →

Indirect evidence

“We are a leading cybersecurity services organization with more than a decade of proven expertise in consulting, solution implementation and managed services.”

Source: RevenueBase Database · checked Sep 27, 2026
19Partial evidenceLondon, United KingdomHQ checked Sep 27, 202611-5015 contacts →

Partial evidence

“is an ISO 9001:2015 and ISO/IEC 27001:2022 certified, DPIIT-recognized cybersecurity company delivering structured External Vulnerability Assessment & Penetration Testing (VAPT)…”

Source: RevenueBase Database · checked Sep 27, 2026
20Partial evidenceHolborn, United KingdomHQ checked Sep 27, 20261-1013 contacts →

Partial evidence

“Laburity: Cyber Security Research and Services Company.”

Source: RevenueBase Database · checked Sep 27, 2026
21Partial evidenceMilton Keynes, United KingdomHQ checked Sep 27, 202611-5012 contacts →

Partial evidence

“We offer specialist CREST & CHECK Approved Penetration Testing services in order to secure our clients most critical assets.”

Source: RevenueBase Database · checked Sep 27, 2026
22Strong evidenceBelfast, United KingdomHQ checked Sep 27, 202611-5012 contacts →

Strong evidence

“Cyber Guarded is a vendor independent business which provides Cyber Security auditing and testing services.”

Source: RevenueBase Database · checked Sep 27, 2026
23Partial evidenceLondon, United KingdomHQ checked Sep 27, 202611-5012 contacts →

Partial evidence

“At Cyber Armed Security, we protect organisations worldwide from evolving cyber threats through intelligence-driven ethical hacking.”

Source: RevenueBase Database · checked Sep 27, 2026
24Indirect evidenceBath, United KingdomHQ checked Sep 27, 202611-5011 contacts →

Indirect evidence

“At Mobius Binary we care about your reputation and the loss that could result from violating your digital boundaries.”

Source: RevenueBase Database · checked Sep 27, 2026
25Partial evidenceSouthend-on-sea, United KingdomHQ checked Sep 27, 202611-5011 contacts →

Partial evidence

“Cyber Trust | Your security team around your existing IT Cyber Trust is a UK‑based cyber security firm that works alongside your existing IT team or technology provider.”

Source: RevenueBase Database · checked Sep 27, 2026

Showing 25 of 213 cloud security testing services based in the United Kingdom

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Cloud security testing services based in the United Kingdom at a glance

As of Sep 27, 2026
22.3%Verified-email coverage
12.3Average contacts per company
1-10Median size (employees)
33.8%Largest-city concentration · London
Sep 27, 2026Page data refreshed

Companies by employee count

1-10
133
11-50
65
51-200
7
201-500
3
501-1,000
2
1,001-5,000
2
5,001-10,000
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 213 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 cloud security testing services, 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 “cloud security testing services”. 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 cloud security testing services), 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 cloud security testing 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 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, 585 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.

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 cloud security testing services, 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 cloud security testing services are there based in the United Kingdom?

RevenueBase identified 213 cloud security testing 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?

Cyberfort, headquartered in Thatcham, tops this list with the largest team on record.

Which city has the most cloud security testing services?

London leads with 72 headquartered companies, followed by Manchester (12) and Birmingham (9).

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 585 verified decision-maker contacts tracked across these 213 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.