Company lists · Data refreshed September 2026

Top 25 Healthcare penetration testing companies based in the United Kingdom

Name: Healthcare penetration testing companies based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 16, 2026 150 companies tracked

RevenueBase identified 150 healthcare penetration testing companies headquartered in the United Kingdom as of September 2026 and tracks 1,892 professional contacts across them, including 333 with verified work emails. London is the largest hub.

This list covers healthcare penetration testing companies 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 16, 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 16, 2026 86% judged on-target in blind review

150Companies

1,892Contacts tracked

333Verified emails

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The 25 largest healthcare penetration testing companies based in the United Kingdom

Ranked by team size

Top 25 of 150 healthcare penetration testing companies based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 16, 2026. RevenueBase Smart Search rates how each company's information relates to healthcare penetration testing companies: 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.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Rootshell Security	Partial evidence	Basingstoke, United KingdomHQ checked Sep 16, 2026	51-200	49 contacts →
	Partial evidence “Human-Led Continuous Testing.” Source: RevenueBase Database · checked Sep 16, 2026
2	Onsecurity	Strong evidence	Bristol, United KingdomHQ checked Sep 16, 2026	51-200	39 contacts →
	Strong evidence “OnSecurity offers CREST-accredited AI Augmented Penetration Testing, all whilst harnessing technology to simplify the management and delivery of pentesting.” Source: RevenueBase Database · checked Sep 16, 2026
3	Secarma LTD	Indirect evidence	Manchester, United KingdomHQ checked Sep 16, 2026	11-50	36 contacts →
	Indirect evidence “Secarma exists to keep the world safe.” Source: RevenueBase Database · checked Sep 16, 2026
4	Notsosecure Training Part Of Claranet Cyber Security	Indirect evidence	London, United KingdomHQ checked Sep 16, 2026	1,001-5,000	33 contacts →
	Indirect evidence “NotSoSecure Training, part of Claranet Cyber Security.” Source: RevenueBase Database · checked Sep 16, 2026
5	Aristi	Indirect evidence	Birmingham, United KingdomHQ checked Sep 16, 2026	11-50	32 contacts →
	Indirect evidence “Aristi is a specialist provider of cyber security services with over 17 years of experience.” Source: RevenueBase Database · checked Sep 16, 2026
6	Citation Cyber	Indirect evidence	Lancaster, United KingdomHQ checked Sep 16, 2026	11-50	30 contacts →
	Indirect evidence “Cyber security can feel overwhelming.” Source: RevenueBase Database · checked Sep 16, 2026
7	Procheckup PCU	Indirect evidence	Portsmouth, United KingdomHQ checked Sep 16, 2026	11-50	29 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 16, 2026
8	Cybercrowd	Partial evidence	Newbury, United KingdomHQ checked Sep 16, 2026	11-50	23 contacts →
	Partial 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 16, 2026
9	Toro Solutions	Partial evidence	London, United KingdomHQ checked Sep 16, 2026	11-50	23 contacts →
	Partial 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 16, 2026
10	Rightcue	Indirect evidence	Basingstoke, United KingdomHQ checked Sep 16, 2026	11-50	20 contacts →
	Indirect evidence “We help organisations achieve business-focused cybersecurity compliance across various industry and regulatory frameworks with successful stakeholder management, particularly in…” Source: RevenueBase Database · checked Sep 16, 2026
11	Halo I.S	Indirect evidence	Leeds, United KingdomHQ checked Sep 16, 2026	11-50	19 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 16, 2026
12	th4ts3cur1ty.company	Indirect evidence	London, United KingdomHQ checked Sep 16, 2026	11-50	18 contacts →
	Indirect evidence “th4ts3cur1ty.company supplies cyber security services internationally.” Source: RevenueBase Database · checked Sep 16, 2026
13	Eh1-Infotech Cybersecurity	Strong evidence	London, United KingdomHQ checked Sep 16, 2026	11-50	15 contacts →
	Strong 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 16, 2026
14	Periculo	Indirect evidence	United KingdomHQ checked Sep 16, 2026	11-50	13 contacts →
	Indirect evidence “Periculo provides specialised cybersecurity for digital health, defence and AI organisations, combining technical expertise and sector-specific knowledge to ensure compliance…” Source: RevenueBase Database · checked Sep 16, 2026
15	Laburity	Indirect evidence	Holborn, United KingdomHQ checked Sep 16, 2026	1-10	13 contacts →
	Indirect evidence “Laburity: Cyber Security Research and Services Company.” Source: RevenueBase Database · checked Sep 16, 2026
16	Cyber Guarded LTD	Partial evidence	Belfast, United KingdomHQ checked Sep 16, 2026	11-50	12 contacts →
	Partial evidence “Cyber Guarded is a vendor independent business which provides Cyber Security auditing and testing services.” Source: RevenueBase Database · checked Sep 16, 2026
17	Ruptura Infosecurity	Strong evidence	Milton Keynes, United KingdomHQ checked Sep 16, 2026	11-50	12 contacts →
	Strong evidence “We offer specialist CREST & CHECK Approved Penetration Testing services in order to secure our clients most critical assets.” Source: RevenueBase Database · checked Sep 16, 2026
18	Cyber Armed Security	Indirect evidence	London, United KingdomHQ checked Sep 16, 2026	11-50	12 contacts →
	Indirect evidence “At Cyber Armed Security, we protect organisations worldwide from evolving cyber threats through intelligence-driven ethical hacking.” Source: RevenueBase Database · checked Sep 16, 2026
19	Mobius Binary	Indirect evidence	Bath, United KingdomHQ checked Sep 16, 2026	11-50	11 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 16, 2026
20	Firesand LTD	Indirect evidence	Newport Pagnell, United KingdomHQ checked Sep 16, 2026	1-10	9 contacts →
	Indirect evidence “At Firesand Ltd, we support iGaming operators, platform providers, and regulated digital businesses with trusted cybersecurity, compliance, and risk management services worldwide.” Source: RevenueBase Database · checked Sep 16, 2026
21	Xray Cybersecurity	Strong evidence	London, United KingdomHQ checked Sep 16, 2026	11-50	8 contacts →
	Strong evidence “We provide a wide range of Penetration Testing Services: External & Internal Network Pentest, Application Pentest and Social Engineering Attacks.” Source: RevenueBase Database · checked Sep 16, 2026
22	Kelltron Consulting Services	Indirect evidence	Aylesbury, United KingdomHQ checked Sep 16, 2026	11-50	7 contacts →
	Indirect evidence “Kelltron Consulting Services is a globally recognized cybersecurity consulting firm with a strong presence in the United Kingdom, United States, and India.” Source: RevenueBase Database · checked Sep 16, 2026
23	Fidus Information Security	Indirect evidence	Cambridge, United KingdomHQ checked Sep 16, 2026	11-50	7 contacts →
	Indirect evidence “Fidus Information Security is a provider of world-class cyber security services which enables businesses to proactively identify and manage their information security risks.” Source: RevenueBase Database · checked Sep 16, 2026
24	Threat Protect	Indirect evidence	London, United KingdomHQ checked Sep 16, 2026	1-10	7 contacts →
	Indirect evidence “Threat Protect is a vendor-agnostic cybersecurity, compliance and AI governance partner based in London, working with organisations across finance, legal, energy, pharma…” Source: RevenueBase Database · checked Sep 16, 2026
25	Secure Debug	Indirect evidence	Cranfield, United KingdomHQ checked Sep 16, 2026	11-50	6 contacts →
	Indirect evidence “Secure Debug: Your Full-Spectrum Cybersecurity Guardian!” Source: RevenueBase Database · checked Sep 16, 2026

RevenueBase Smart Search

RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: healthcare penetration testing companies. Every row carries its rating and the description the rating was read from, so each one can be checked rather than taken on trust.

Strong evidence: The company's own public description of its business names healthcare penetration testing companies.
Partial evidence: Its own public description names part of healthcare penetration testing companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name healthcare penetration testing companies. The match rests on the rest of the company's public profile rather than the one sentence quoted here, so this is the rating to check first.

RevenueBase Smart Search is how these lists are built: RevenueBase's data engine and AI assemble the companies that match a category defined in a user's own words, so a list can be about what companies actually do rather than about whichever industry code they were filed under.

Showing 25 of 150 healthcare penetration testing companies based in the United Kingdom

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Healthcare penetration testing companies based in the United Kingdom at a glance

As of Sep 16, 2026

17.6%Verified-email coverage

12.6Average contacts per company

1-10Median size (employees)

41.3%Largest-city concentration · London

Sep 16, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

1,001-5,000

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 150 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 healthcare penetration testing companies, 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 “healthcare penetration testing companies”. 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 healthcare penetration testing companies), 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 healthcare penetration testing companies, 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, 333 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 16, 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.

Healthcare penetration testing companies by metro

Healthcare penetration testing companies in London62

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 healthcare penetration testing companies, 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 healthcare penetration testing companies are there based in the United Kingdom?

RevenueBase identified 150 healthcare penetration testing companies 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?

Rootshell Security, headquartered in Basingstoke, tops this list with the largest team on record.

Which city has the most healthcare penetration testing companies?

London leads with 62 headquartered companies, followed by Manchester (6) and Cheltenham (4).

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 333 verified decision-maker contacts tracked across these 150 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 16, 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.