Company lists · Data refreshed September 2026

Top 23 Plc security consulting companies based in London, United Kingdom

RevenueBase identified 69 plc security consulting companies headquartered in London, United Kingdom as of September 2026 and tracks 564 professional contacts across them, including 256 with verified work emails. Across the United Kingdom, London is the largest hub for this category.

This list covers plc security consulting 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 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.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 29, 2026 86% judged on-target in blind review
69Companies
564Contacts tracked
256Verified emails
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The 23 largest plc security consulting companies based in London, United Kingdom

Ranked by team size
Top 23 of 69 plc security consulting companies based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 29, 2026. RevenueBase Smart Search rates how each company's information relates to plc security consulting 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Partial evidenceLondon, United KingdomHQ checked Sep 29, 202651-200159 contacts →

Partial evidence

“QCIC is an award-winning global engineering firm specialising in designing, building and running security systems.”

Source: RevenueBase Database · checked Sep 29, 2026
2Indirect evidenceLondon, United KingdomHQ checked Sep 29, 202651-200126 contacts →

Indirect evidence

“We are TRPGLOBAL, your strategic partner in helping you with the complexities of risk management.”

Source: RevenueBase Database · checked Sep 29, 2026
3Strong evidenceLondon, United KingdomHQ checked Sep 29, 202651-20044 contacts →

Strong evidence

“CornerStone is an award winning, independent, security and digital building consulting firm with headquarters in the UK.”

Source: RevenueBase Database · checked Sep 29, 2026
4Partial evidenceLondon, United KingdomHQ checked Sep 29, 202611-5020 contacts →

Partial evidence

“LMS Security are a fully Independent, privately owned, Internationally recognised and accredited Security Consultancy; owned and built by Electronic and Physical Security…”

Source: RevenueBase Database · checked Sep 29, 2026
5Partial evidenceLondon, United KingdomHQ checked Sep 29, 202611-5020 contacts →

Partial evidence

“Formed in 2018, NGS (UK) Ltd are independent, Next Generation Security trusted advisors, providing all-encompassing solutions from the perimeter to the endpoint.”

Source: RevenueBase Database · checked Sep 29, 2026
6Strong evidenceLondon, United KingdomHQ checked Sep 29, 20261-1010 contacts →

Strong evidence

“We are a UK-based Cyber Security company offering a comprehensive portfolio specialising in innovative solutions for Penetration Testing, Training, Compliance, Consulting, and…”

Source: RevenueBase Database · checked Sep 29, 2026
7Strong evidenceLondon, United KingdomHQ checked Sep 29, 202611-508 contacts →

Strong 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, 2026
8Strong evidenceLondon, United KingdomHQ checked Sep 29, 20261-105 contacts →

Strong evidence

“At Harpoon Consulting, OT security isn’t just part of what we do, it’s all we do.”

Source: RevenueBase Database · checked Sep 29, 2026
9Indirect evidenceLondon, United KingdomHQ checked Sep 29, 202611-505 contacts →

Indirect evidence

“Amovada is a leading consultancy specialising in Operational Technology (OT) Cybersecurity for global manufacturing companies.”

Source: RevenueBase Database · checked Sep 29, 2026
10Partial evidenceLondon, United KingdomHQ checked Sep 29, 20261-104 contacts →

Partial evidence

“Westlands Advisory (WA) works exclusively on security market issues, helping industry, government and security professionals to minimise business risk and improve performance…”

Source: RevenueBase Database · checked Sep 29, 2026
11Partial evidenceLondon, United KingdomHQ checked Sep 29, 20261-103 contacts →

Partial evidence

“Trinity OT Security specialises in cybersecurity solutions, system integration and professional services for Operational Technology (OT) environments.”

Source: RevenueBase Database · checked Sep 29, 2026
12Indirect evidenceLondon, United KingdomHQ checked Sep 29, 20261-103 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 29, 2026
13Indirect evidenceLondon, United KingdomHQ checked Sep 29, 20261-103 contacts →

Indirect evidence

“PBOSECURE (Trading as CYBERSYS TECHNOLOGIES)** is a UK-based industrial solutions company specialising in Vapor Recovery Units (VRU), emission reduction technologies, and energy…”

Source: RevenueBase Database · checked Sep 29, 2026
14Strong evidenceLondon, United KingdomHQ checked Sep 29, 202611-502 contacts →

Strong evidence

“HMH Consulting LLC is a Texas-based security consultancy operating at the intersection of physical and cyber risk, serving high-net-worth individuals, luxury retailers…”

Source: RevenueBase Database · checked Sep 29, 2026
15Partial evidenceLondon, United KingdomHQ checked Sep 29, 202611-502 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 29, 2026
16Partial evidenceLondon, United KingdomHQ checked Sep 29, 20261-102 contacts →

Partial evidence

“We are an Information Security Consultancy specialised in the fields of Information Security Management, IT Security Architecture, Intellectual Property Protection and Digital…”

Source: RevenueBase Database · checked Sep 29, 2026
17Partial evidenceLondon, United KingdomHQ checked Sep 29, 20261-102 contacts →

Partial evidence

“Centilon Limited provides leading edge security solutions, consultancy and bespoke training to organisations that have a requirement to secure & manage their network…”

Source: RevenueBase Database · checked Sep 29, 2026
18Partial evidenceLondon, United KingdomHQ checked Sep 29, 2026201-5001 contacts →

Partial evidence

“EST Applied Intelligence is a specialist enterprise security consultancy dedicated to building strategic resilience in an increasingly complex digital world.”

Source: RevenueBase Database · checked Sep 29, 2026
19Strong evidenceLondon, United KingdomHQ checked Sep 29, 202611-501 contacts →

Strong evidence

“Offensive security consulting for consultancies, MSSPs, corporates & governments.”

Source: RevenueBase Database · checked Sep 29, 2026
20Partial evidenceLondon, United KingdomHQ checked Sep 29, 20261-101 contacts →

Partial evidence

“Organisations are increasingly operating in hostile environments which often leave them vulnerable to a number of security threats.”

Source: RevenueBase Database · checked Sep 29, 2026
21Strong evidenceLondon, United KingdomHQ checked Sep 29, 20261-101 contacts →

Strong evidence

“Qantara is industry-led consulting firm specialising in IT and OT security.”

Source: RevenueBase Database · checked Sep 29, 2026
22Partial evidenceLondon, United KingdomHQ checked Sep 29, 20261-101 contacts →

Partial evidence

“Our security consultants have a wide range of expertise across a number of areas related to information security and compliance.”

Source: RevenueBase Database · checked Sep 29, 2026
23Indirect evidenceLondon, United KingdomHQ checked Sep 29, 20261-101 contacts →

Indirect evidence

“GSA Cyber Secure has joined forces with its sister brands under a new combined name: GSA Global.”

Source: RevenueBase Database · checked Sep 29, 2026

Showing 23 of 69 plc security consulting companies based in London, United Kingdom

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Plc security consulting companies based in London, United Kingdom at a glance

As of Sep 29, 2026
45.4%Verified-email coverage
8.2Average contacts per company
1-10Median size (employees)
Sep 29, 2026Page data refreshed

Companies by employee count

1-10
42
11-50
18
51-200
7
201-500
2

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 69 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 plc security consulting 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 “plc security consulting 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 plc security consulting 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 plc security consulting 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, 256 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 plc security consulting 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 plc security consulting companies are there based in London, United Kingdom?

RevenueBase identified 69 plc security consulting 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?

QCIC, headquartered in London, tops this list with the largest team on record.

Which city in the United Kingdom has the most plc security consulting companies?

London leads the United Kingdom with 69 headquartered companies, followed by Manchester (7) and Birmingham (4).

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 256 verified decision-maker contacts tracked across these 69 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.