Company lists · Data refreshed September 2026

Top 25 Managed security service providers based in London, United Kingdom

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

Compiled by the RevenueBase Data Team Data refreshed Sep 5, 2026 564 companies tracked

RevenueBase identified 564 managed security service providers headquartered in London, United Kingdom as of September 2026 and tracks 7,480 professional contacts across them, including 2,291 with verified work emails. London is the largest hub.

This list covers managed security service providers 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, how directly it supports the match, 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 SmartSearch, 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 Match evidence on every row Refreshed Sep 5, 2026 86% judged on-target in blind review

564Companies

7,480Contacts tracked

2,291Verified emails

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The 25 largest managed security service providers based in London, United Kingdom

Ranked by team size

Top 25 of 564 managed security service providers based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 5, 2026. Evidence rates how directly each company's own description names managed security service providers: strong (names it), partial (names part of it), indirect (matched on its full profile rather than the summary shown). Click a count to unlock that company's people.
#	Company	Headquarters	Employees	Contacts
1	S-RmPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	351
	“S-RM is a global intelligence and cyber security consultancy.” Source: company website · checked Sep 5, 2026
2	ObrelaPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	242
	“Obrela Security Industries is a global provider of cyber security services.” Source: company website · checked Sep 5, 2026
3	IntragenStrong evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	190
	“Intragen is a cyber security business focused on managed Identity solutions and services.” Source: company website · checked Sep 5, 2026
4	Deepcytes Cyber Labs UKIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	177
	“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: company website · checked Sep 5, 2026
5	Bulletproof Cyber SecurityIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	123
	“Bulletproof is now part of WorkNest Secure.” Source: company website · checked Sep 5, 2026
6	Doherty AssociatesStrong evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	113
	“Doherty Associates is a Managed Service Provider delivering IT support, cyber security and AI enablement ‘beyond the call’.” Source: company website · checked Sep 5, 2026
7	RED SiftIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	109
	“Red Sift enables organizations to anticipate, respond to, and recover from cyber attacks while continuing to operate effectively.” Source: company website · checked Sep 5, 2026
8	ConoscoIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	105
	“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: company website · checked Sep 5, 2026
9	OryxalignIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	99
	“OryxAlign creates true alignment that delivers the right outcomes for all.” Source: company website · checked Sep 5, 2026
10	Caretower An Integrity360 CompanyPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	97
	“As an independent IT security specialist, Caretower provide comprehensive solutions to individual problems, thus allowing our recommendations to be unbiased.” Source: company website · checked Sep 5, 2026
11	CyberoneStrong evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	96
	“CyberOne is a Microsoft Security Elite Partner and one of only 100 global Microsoft partners recognised with Microsoft-Verified Managed XDR solution status.” Source: company website · checked Sep 5, 2026
12	Titania LTDPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	88
	“Dedicated to securing the networks society depends on.” Source: company website · checked Sep 5, 2026
13	ITC SecurePartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	87
	“ITC Secure is an advisory-led cyber security services company.” Source: company website · checked Sep 5, 2026
14	CybersmartIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	84
	“Cybersecurity should be simple.” Source: company website · checked Sep 5, 2026
15	CybanetixStrong evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	79
	“Cybanetix is a leading provider of managed Cyber Security Service and hosted SIEM and breach detection services.” Source: company website · checked Sep 5, 2026
16	White HAT An Epam CompanyPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	77
	“White Hat, part of the EPAM group, is an award-winning cyber intelligence and offensive security company that leverages an attacker’s perspective to shape innovative, proactive…” Source: company website · checked Sep 5, 2026
17	CovertswarmIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	64
	“YOU DESERVE TO BE HACKED®.” Source: company website · checked Sep 5, 2026
18	Cyro CyberPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	62
	“Cyro Cyber are your cyber security Guardians.” Source: company website · checked Sep 5, 2026
19	IntruderStrong evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	61
	“Intruder's continuous exposure management platform helps security, IT, and engineering teams stop breaches before they start.” Source: company website · checked Sep 5, 2026
20	TechforingIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	61
	“TechForing is a global leader in cybersecurity, dedicated to protecting digital assets and ensuring a safer cyberspace for businesses and individuals.” Source: company website · checked Sep 5, 2026
21	DainttaIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	60
	“We provide deep expertise with technical and business specialists to help clients secure and protect the UK.” Source: company website · checked Sep 5, 2026
22	Garrison NOW A Part Of EverfoxIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	60
	“Garrison is a London-based cybersecurity company founded in 2014 by David Garfield (CEO) and Henry Harrison (Chief Scientist).” Source: company website · checked Sep 5, 2026
23	RiversafePartial evidence	London, United KingdomHQ checked Sep 5, 2026	11-50	57
	“We deliver services in Cybersecurity, Application Security and DevOps and are trusted by some of the world’s leading brands to maximise the value of their security investments and…” Source: company website · checked Sep 5, 2026
24	CyberowlPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	52
	“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: company website · checked Sep 5, 2026
25	HexegicIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	52
	“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: company website · checked Sep 5, 2026

Showing 25 of 564 managed security service providers based in London, United Kingdom

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Managed security service providers based in London, United Kingdom at a glance

As of Sep 5, 2026

1-10Median size (employees)

LondonLargest hub · 564 HQs

Contacts with mobile numbers

Sep 5, 2026Data refreshed

Companies by employee count

1-10

309

11-50

180

51-200

201-500

501-1,000

1,001-5,000

10001+

Email recency for this list is measured across the whole United Kingdom list rather than this city, so it is reported there. Company counts and contact totals on this page are exact for London, over 564 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 security service providers, so some rows will be adjacent to the category rather than pure plays. The description and evidence 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 SmartSearch, 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 security service providers”. Matching reads each company's description, not its industry code or its name.
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 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 an evidence 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, 2,291 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 in the United Kingdom

Managed security service providers in London564
Managed security service providers in Manchester59
Managed security service providers in Birmingham31

Frequently asked

How many managed security service providers are there based in London, United Kingdom?

RevenueBase identified 564 managed security service providers 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?

S-Rm, headquartered in London, 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 2,291 verified decision-maker contacts tracked across these 564 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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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 SmartSearch, 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.