Company lists · Data refreshed September 2026

Top 25 Managed network security companies based in London, United Kingdom

Name: Managed network security companies based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 28, 2026 90 companies tracked

RevenueBase identified 90 managed network security companies headquartered in London, United Kingdom as of September 2026 and tracks 895 professional contacts across them, including 318 with verified work emails. Across the United Kingdom, London is the largest hub for this category.

This list covers managed network security companies 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 28, 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 28, 2026 86% judged on-target in blind review

90Companies

895Contacts tracked

318Verified emails

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The 25 largest managed network security companies based in London, United Kingdom

Ranked by team size

Top 25 of 90 managed network security companies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to managed network security 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	Obrela	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	201-500	242 contacts →
	Partial evidence “Obrela Security Industries is a global provider of cyber security services.” Source: RevenueBase Database · checked Sep 28, 2026
2	Threatspike	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	61 contacts →
	Strong evidence “ThreatSpike is the world's first AI-managed IT and security platform, replacing the legacy MSP model entirely.” Source: RevenueBase Database · checked Sep 28, 2026
3	Redscan, A Kroll Business	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	51 contacts →
	Strong evidence “Redscan is an award-winning provider of managed security services, specialising in Managed Detection and Response, Penetration Testing and Red Teaming.” Source: RevenueBase Database · checked Sep 28, 2026
4	J2 Mssp	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	29 contacts →
	Partial evidence “Cyber security is the modern business' greatest risk.” Source: RevenueBase Database · checked Sep 28, 2026
5	Nanjgel Solutions	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	24 contacts →
	Partial evidence “Nanjgel Solutions is focused on delivering the best IT security for businesses.” Source: RevenueBase Database · checked Sep 28, 2026
6	Proxar IT Cloud Solutions Support Consulting	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	20 contacts →
	Partial evidence “Proxar IT Consulting provides IT services and security solutions for businesses of all sizes.” Source: RevenueBase Database · checked Sep 28, 2026
7	Sinevis	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	17 contacts →
	Partial 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 28, 2026
8	CST Limited Computer Security Technology	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	17 contacts →
	Partial evidence “We are a London based specialist supplier of cyber defence solution and information security services.” Source: RevenueBase Database · checked Sep 28, 2026
9	Alltime Technologies Limited	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	15 contacts →
	Strong evidence “Alltime Technologies Limited is a London based Cyber Security focused Managed Services and Consultancy provider.” Source: RevenueBase Database · checked Sep 28, 2026
10	PC Power International LTD	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	10 contacts →
	Strong evidence “PC POWER INTERNATIONAL LTD is a computer & network security company based in the City, London, United Kingdom.” Source: RevenueBase Database · checked Sep 28, 2026
11	Defenx	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	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 28, 2026
12	Cyberseer	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	8 contacts →
	Strong evidence “Cyberseer offers Advanced Threat Detection and a 24×7 Managed Security Service (MSS).” Source: RevenueBase Database · checked Sep 28, 2026
13	Rocksec360	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	8 contacts →
	Indirect evidence “At RockSec360, our vision is simple and focused: Small and mid-sized businesses deserve complete confidence that their sensitive data, intellectual property, and business assets…” Source: RevenueBase Database · checked Sep 28, 2026
14	Fulcrum	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	1-10	8 contacts →
	Indirect evidence “Fulcrum's sole purpose is to take the tech burden away from our clients.” Source: RevenueBase Database · checked Sep 28, 2026
15	ISUMO	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	7 contacts →
	Strong evidence “ISUMO leverage industry leading technologies to ensure optimum security, availability and compliance throughout your entire network.” Source: RevenueBase Database · checked Sep 28, 2026
16	Threat Protect	Indirect evidence	London, United KingdomHQ checked Sep 28, 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 28, 2026
17	Bell ICT	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	1-10	5 contacts →
	Partial evidence “From the little niggles to the large networks It’s the little things that are vital whether you have a website, online accounts or any type of web-based infrastructure.” Source: RevenueBase Database · checked Sep 28, 2026
18	CM Security	Strong evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	5 contacts →
	Strong evidence “CM Security provides a Managed Service of Cloud Security and Protection combined with Professional Services from specialised professionals who’ll help you implement the right mix…” Source: RevenueBase Database · checked Sep 28, 2026
19	Rexel Cybersecurity	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	5 contacts →
	Indirect evidence “At Rexel Cyber we help businesses fight the constant threat of cyber attack and data breach.” Source: RevenueBase Database · checked Sep 28, 2026
20	Grove Group	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	51-200	3 contacts →
	Indirect evidence “Grove unlocks business success by defending our customers with the most advanced cybersecurity solutions in the market place today.” Source: RevenueBase Database · checked Sep 28, 2026
21	Burstfire Networks Limited	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	1-10	3 contacts →
	Indirect evidence “We know running a business is hard enough without worrying about cyber threats and IT headaches.” Source: RevenueBase Database · checked Sep 28, 2026
22	Threatproof	Indirect evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	2 contacts →
	Indirect evidence “At Threatproof, our mission is to redefine cybersecurity for businesses of all sizes.” Source: RevenueBase Database · checked Sep 28, 2026
23	Sesseto Limited	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	2 contacts →
	Partial evidence “Good security consultants are difficult to find, expensive to employ and hard to keep, but we believe that your business doesn’t have to incur a high cost of delivery in order to…” Source: RevenueBase Database · checked Sep 28, 2026
24	Cansol Consulting	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	11-50	2 contacts →
	Partial evidence “Founded in 2017, Cansol is a Cyber Security company with office in London and Dubai.” Source: RevenueBase Database · checked Sep 28, 2026
25	Essential Security UK LTD	Partial evidence	London, United KingdomHQ checked Sep 28, 2026	1-10	2 contacts →
	Partial evidence “Essential Security is a unique company in that we offer a specialised and confidential service meeting your bespoke technological and communications requirements.” Source: RevenueBase Database · checked Sep 28, 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: managed network security 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 managed network security companies.
Partial evidence: Its own public description names part of managed network security companies, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name managed network security 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 90 managed network security companies based in London, United Kingdom

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Managed network security companies based in London, United Kingdom at a glance

As of Sep 28, 2026

35.5%Verified-email coverage

9.9Average contacts per company

11-50Median size (employees)

Sep 28, 2026Page data refreshed

Companies by employee count

1-10

11-50

51-200

201-500

501-1,000

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 90 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 managed network security 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 London, United Kingdom whose own description of what they do matches “managed network security 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 managed network security 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 managed network security companies, 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, 318 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 28, 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 managed network security 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 managed network security companies are there based in London, United Kingdom?

RevenueBase identified 90 managed network security companies 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 managed network security companies?

London leads the United Kingdom with 90 headquartered companies, followed by Manchester (9) and Birmingham (5).

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 318 verified decision-maker contacts tracked across these 90 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 28, 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.