Company lists · Data refreshed September 2026
Top 24 Operational technology security firms based in London, United Kingdom
RevenueBase identified 108 operational technology security firms headquartered in London, United Kingdom as of September 2026 and tracks 2,742 professional contacts across them, including 492 with verified work emails. Across the United Kingdom, London is the largest hub for this category.
This list covers operational technology security firms headquartered in London, 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 29, 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 24 largest operational technology security firms based in London, United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 242 contacts → | ||||
Partial evidence “Obrela Security Industries is a global provider of cyber security services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 123 contacts → | ||||
Indirect evidence “Bulletproof is now part of WorkNest Secure.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 52 contacts → | ||||
Partial evidence “CyberOwl helps asset operators in the maritime and critical national infrastructure sectors gain visibility, cyber security and cyber compliance of systems on their distributed…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 52 contacts → | ||||
Indirect evidence “At Hexegic we are not just passionate about protecting data through our Cyber services we are passionate about helping companies release the potential of the data they hold…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 36 contacts → | ||||
Partial evidence “The future of IoT/OT security is here.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 21 contacts → | ||||
Partial evidence “Templar Executives is an award winning, international Cyber Security advisory services and solutions company operating at the highest levels across the public and private sectors.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 7 | 20 contacts → | ||||
Partial evidence “Cyber Energia – Your Comprehensive Cyber Security Solution for a smart & sustainable energy market Cyber Energia is a dynamic managed security service provider offering OT / SCADA…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 18 contacts → | ||||
Indirect evidence “Infosec K2K safeguards your organisation’s most valuable assets with tailored cybersecurity solutions.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 17 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 29, 2026Thanks. The Data Team will review it. | |||||
| 10 | 17 contacts → | ||||
Partial evidence “We are a London based specialist supplier of cyber defence solution and information security services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 16 contacts → | ||||
Indirect evidence “Barefoot Cyber is the strategic partner for senior leaders who recognize that a cybersecurity attack is not just a technical failure, but a direct threat to their revenue…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 15 contacts → | ||||
Indirect evidence “Who We Are DataSixth delivers Cybersecurity Intelligence.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 13 contacts → | ||||
Indirect evidence “Our mission at SOCGuardians is to empower organizations to operate confidently in a digital world by providing cutting-edge cybersecurity services.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 14 | 12 contacts → | ||||
Indirect evidence “deltaflare helps critical infrastructure operators modernise securely.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 15 | 12 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 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 11 contacts → | ||||
Partial evidence “Disclosure Cybersecurity Ltd is a specialist cyber security company, formed by professionals with extensive experience and wide exposure in the cyber security market.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 11 contacts → | ||||
Strong evidence “CyberPrism safeguards your business-critical Operational Technology (OT).” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 11 contacts → | ||||
Strong evidence “We are a next-gen Operational Technology (OT) cybersecurity leader focused on safeguarding industrial environments so that we can fulfil our purpose: Provide best-in-class OT…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 19 | 10 contacts → | ||||
Partial evidence “Defenx is an IT company that has an extensive background in providing businesses with cloud based security solutions and support for their digital infrastructure.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 10 contacts → | ||||
Partial evidence “swIDch stops OT attacks at the access layer by securing the most vulnerable endpoints in critical infrastructure.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 21 | 8 contacts → | ||||
Partial evidence “iCyberDefence is a boutique cybersecurity services firm that offers a wide range of security consulting and security engineering services with the necessary products and tools.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 22 | 8 contacts → | ||||
Indirect evidence “Community of Azure users.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 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 29, 2026Thanks. The Data Team will review it. | |||||
| 24 | 6 contacts → | ||||
Indirect evidence Source: RevenueBase Database · checked Sep 29, 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: operational technology security firms. 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 operational technology security firms.
- Partial evidence
- Its own public description names part of operational technology security firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name operational technology security firms. 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 24 of 108 operational technology security firms based in London, United Kingdom
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Operational technology security firms based in London, United Kingdom at a glance
As of Sep 29, 2026Companies by employee count
Email recency for this list is measured across the whole United Kingdom list rather than for London, so it is reported there. Company counts and contact totals on this page are exact for London, over 108 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 operational technology security firms, 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 London, United Kingdom whose own description of what they do matches “operational technology security firms”. 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 operational technology security firms), 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 operational technology security firms, and records with no verified work email. Companies headquartered outside London 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, 492 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 29, 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 operational technology security firms, 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 operational technology security firms are there based in London, United Kingdom?
RevenueBase identified 108 operational technology security firms headquartered in London, 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?
Obrela, headquartered in London, tops this list with the largest team on record.
Which city in the United Kingdom has the most operational technology security firms?
London leads the United Kingdom with 108 headquartered companies, followed by Manchester (11) and Aberdeen (6).
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 492 verified decision-maker contacts tracked across these 108 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 29, 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.
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