Company lists · Data refreshed September 2026
Top 25 Cyber defence companies based in the United Kingdom
RevenueBase identified 857 cyber defence companies headquartered in the United Kingdom as of September 2026 and tracks 21,514 professional contacts across them, including 7,719 with verified work emails. London is the largest hub.
This list covers cyber defence 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 21, 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 cyber defence companies based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 4,925 contacts → | ||||
Partial evidence “Sophos is a cybersecurity leader defending organizations globally with an AI-driven platform and expert-led services.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 2 | 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 21, 2026Thanks. The Data Team will review it. | |||||
| 3 | 679 contacts → | ||||
Partial evidence “At Roke, we stand at the forefront of defence and security, delivering cutting-edge intelligence and engineering solutions that protect nations, troops, borders, and businesses.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 4 | 640 contacts → | ||||
Indirect evidence “MASS, part of the Cohort plc group, helps you realise the value of your data.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 5 | 502 contacts → | ||||
Indirect evidence “SecurityHQ, a global cybersecurity company pioneering Security Performance Engineering for stronger operational performance and resilience.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 6 | 351 contacts → | ||||
Partial evidence “S-RM is a global intelligence and cyber security consultancy.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 7 | 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 21, 2026Thanks. The Data Team will review it. | |||||
| 8 | 297 contacts → | ||||
Partial evidence “At Quorum Cyber, we're on a mission to help good people win.” Source: RevenueBase Database · checked Sep 21, 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 21, 2026Thanks. The Data Team will review it. | |||||
| 10 | 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 21, 2026Thanks. The Data Team will review it. | |||||
| 11 | 171 contacts → | ||||
Indirect evidence “Security Blue Team is now Centri.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 12 | 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 21, 2026Thanks. The Data Team will review it. | |||||
| 13 | 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 21, 2026Thanks. The Data Team will review it. | |||||
| 14 | 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 21, 2026Thanks. The Data Team will review it. | |||||
| 15 | 156 contacts → | ||||
Indirect evidence “Performanta is a global cybersecurity and data risk management company dedicated to protecting people where data matters most.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 16 | 156 contacts → | ||||
Partial evidence “CDS Defence & Security is a technical consultancy working to enhance operational effectiveness and bring about behavioural change in the defence sector.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 17 | 143 contacts → | ||||
Strong evidence “Logiq is a UK-based cyber security consultancy and secure managed services provider supporting defence, government, and critical national infrastructure (CNI) organisations where…” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 18 | 130 contacts → | ||||
Indirect evidence “ESUK is a trusted partner to the UK Armed Forces, delivering advanced technology and innovation that strengthen national security and operational advantage.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 19 | 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 21, 2026Thanks. The Data Team will review it. | |||||
| 20 | 123 contacts → | ||||
Indirect evidence “Bulletproof is now part of WorkNest Secure.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 21 | 109 contacts → | ||||
Partial evidence “Red Sift enables organizations to anticipate, respond to, and recover from cyber attacks while continuing to operate effectively.” Source: RevenueBase Database · checked Sep 21, 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 21, 2026Thanks. The Data Team will review it. | |||||
| 23 | 97 contacts → | ||||
Indirect 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 21, 2026Thanks. The Data Team will review it. | |||||
| 24 | 95 contacts → | ||||
Partial evidence “SEP2 is an award-winning UK-based cyber security specialist service provider, powered by a dedicated team of experts available 24/7/365.” Source: RevenueBase Database · checked Sep 21, 2026Thanks. The Data Team will review it. | |||||
| 25 | 88 contacts → | ||||
Indirect evidence “Dedicated to securing the networks society depends on.” Source: RevenueBase Database · checked Sep 21, 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: cyber defence 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 cyber defence companies.
- Partial evidence
- Its own public description names part of cyber defence companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name cyber defence 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 857 cyber defence companies based in the United Kingdom
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Cyber defence companies based in the United Kingdom at a glance
As of Sep 21, 2026Companies by employee count
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 857 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 cyber defence 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 “cyber defence 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 cyber defence 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 cyber defence 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, 7,719 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 21, 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.
Cyber defence companies by metro
- Cyber defence companies in London349
- Cyber defence companies in Manchester29
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 cyber defence 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 cyber defence companies are there based in the United Kingdom?
RevenueBase identified 857 cyber defence 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?
Sophos, headquartered in Abingdon, tops this list with the largest team on record.
Which city has the most cyber defence companies?
London leads with 349 headquartered companies, followed by Manchester (29) and Birmingham (21).
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 7,719 verified decision-maker contacts tracked across these 857 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 21, 2026.
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Cyber defence companies by geography
- Cyber defence companies based in Brisbane, Australia
- Cyber defence companies based in Canberra, Australia
- Cyber defence companies based in Melbourne, Australia
- Cyber defence companies based in Sydney, Australia
- Cyber defence companies based in Calgary, Canada
- Cyber defence companies based in Montreal, Canada
- Cyber defence companies based in Ottawa, Canada
- Cyber defence companies based in Toronto, Canada
- Cyber defence companies based in Vancouver, Canada
- Cyber defence companies based in Ahmedabad, India
- Cyber defence companies based in Bangalore, India
- Cyber defence companies based in Bengaluru, India
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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