Company lists · Data refreshed September 2026
Top 25 Managed security service providers based in the United Kingdom
RevenueBase identified 1,497 managed security service providers headquartered in the United Kingdom as of September 2026 and tracks 28,419 professional contacts across them, including 11,493 with verified work emails and 2,980 with mobile numbers. London is the largest hub.
This list covers managed security service providers 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 5, 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.
The 25 largest managed security service providers based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 4,925 contacts → | ||||
Indirect evidence “Sophos is a cybersecurity leader defending organizations globally with an AI-driven platform and expert-led services.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 2 | 2,355 contacts → | ||||
Indirect evidence “Darktrace is a global leader in AI cybersecurity, providing the essential cybersecurity platform to secure organizations today and for an ever-changing future.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 3 | 764 contacts → | ||||
Partial evidence “MTI provides award-winning, end-to-end technology solutions and services in cyber security and data centre for over 35 years.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 4 | 502 contacts → | ||||
Partial evidence “SecurityHQ, a global cybersecurity company pioneering Security Performance Engineering for stronger operational performance and resilience.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 5 | 351 contacts → | ||||
Partial evidence “S-RM is a global intelligence and cyber security consultancy.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 6 | 303 contacts → | ||||
Partial 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 5, 2026Thanks. The Data Team will review it. | |||||
| 7 | 297 contacts → | ||||
Indirect evidence “At Quorum Cyber, we're on a mission to help good people win.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 8 | 260 contacts → | ||||
Partial evidence “We are a global boutique, specializing exclusively in the convergence of identity-driven security and networking.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 9 | 242 contacts → | ||||
Partial evidence “Obrela Security Industries is a global provider of cyber security services.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 10 | 190 contacts → | ||||
Strong evidence “Intragen is a cyber security business focused on managed Identity solutions and services.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 11 | 178 contacts → | ||||
Strong evidence “24 x 7 Cloud Service Provider & Managed Security Service Provider delivering technology transformation.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 12 | 177 contacts → | ||||
Indirect evidence “Whether you’re a business or an individual, digital threats to your precious data and assets can come in any form - external or internal.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 13 | 168 contacts → | ||||
Partial evidence “Sapphire delivers comprehensive cyber solutions tailored to your needs, spanning across consultancy, managed services, IT/OT and beyond.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 14 | 165 contacts → | ||||
Indirect 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 5, 2026Thanks. The Data Team will review it. | |||||
| 15 | 165 contacts → | ||||
Indirect evidence “FourNet transforms the customer and citizen services people rely on every day.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 16 | 159 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 5, 2026Thanks. The Data Team will review it. | |||||
| 17 | 156 contacts → | ||||
Partial evidence “Performanta is a global cybersecurity and data risk management company dedicated to protecting people where data matters most.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 18 | 125 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 5, 2026Thanks. The Data Team will review it. | |||||
| 19 | 123 contacts → | ||||
Indirect evidence “Bulletproof is now part of WorkNest Secure.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 20 | 113 contacts → | ||||
Strong evidence “Doherty Associates is a Managed Service Provider delivering IT support, cyber security and AI enablement ‘beyond the call’.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 21 | 109 contacts → | ||||
Indirect evidence “Red Sift enables organizations to anticipate, respond to, and recover from cyber attacks while continuing to operate effectively.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 22 | 105 contacts → | ||||
Indirect evidence “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.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 23 | 99 contacts → | ||||
Indirect evidence “OryxAlign creates true alignment that delivers the right outcomes for all.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
| 24 | 97 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 5, 2026Thanks. The Data Team will review it. | |||||
| 25 | 96 contacts → | ||||
Strong evidence “CyberOne is a Microsoft Security Elite Partner and one of only 100 global Microsoft partners recognised with Microsoft-Verified Managed XDR solution status.” Source: RevenueBase Database · checked Sep 5, 2026Thanks. The Data Team will review it. | |||||
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: managed security service providers. 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 managed security service providers.
- Partial evidence
- Its own public description names part of managed security service providers, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name managed security service providers. 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 1,497 managed security service providers based in the United Kingdom
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Managed security service providers based in the United Kingdom at a glance
As of Sep 5, 2026Companies by employee count
Freshness & accuracy
How recently the business emails on this list were verified
Email last verified
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 managed security service providers, 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 “managed security service providers”. 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 managed security service providers), 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 managed security service providers, 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, 11,493 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 5, 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.
Managed security service providers 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 managed security service providers, 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 managed security service providers are there based in the United Kingdom?
RevenueBase identified 1,497 managed security service providers 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?
Sophos, headquartered in Abingdon, tops this list with the largest team on record.
Which city has the most managed security service providers?
London leads with 564 headquartered companies, followed by Manchester (59) and Birmingham (31).
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 11,493 verified decision-maker contacts tracked across these 1,497 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 5, 2026.
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- Managed security service providers based in the Netherlands
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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.
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