Company lists · Data refreshed September 2026
Top 25 Security engineering staffing companies based in London, United Kingdom
RevenueBase identified 189 security engineering staffing companies headquartered in London, United Kingdom as of September 2026 and tracks 5,170 professional contacts across them, including 542 with verified work emails. Across the United Kingdom, London is the largest hub for this category.
This list covers security engineering staffing 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.
The 25 largest security engineering staffing companies based in London, United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 2,673 contacts → | ||||
Indirect evidence “Building tomorrow’s tech landscape together Computer Futures is a Technology specialist, part of SThree, the global STEM workforce consultancy.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 159 contacts → | ||||
Strong evidence “QCIC is an award-winning global engineering firm specialising in designing, building and running security systems.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 108 contacts → | ||||
Indirect evidence “With over 25 years in the technology recruitment sector, Square One is an award-winning specialist recruitment agency.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 97 contacts → | ||||
Partial 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 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 77 contacts → | ||||
Partial evidence “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: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 57 contacts → | ||||
Partial evidence “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: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 7 | 32 contacts → | ||||
Partial evidence “Your partner in cyber security talent, investment and events.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 32 contacts → | ||||
Partial evidence “Founded in 2006, Torrid Networks has been able to establish strong credentials in the area of cyber security products, research, consulting, managed services, education and staff…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 23 contacts → | ||||
Partial evidence “Toro was founded on creating the UK's first Red Team penetration test - and then attacking hundreds of clients by hacking their systems, influencing / social engineering staff and…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 10 | 20 contacts → | ||||
Partial evidence “We connect top cybersecurity and eDiscovery talent at Iceberg Cyber Security with the most innovative companies worldwide.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 18 contacts → | ||||
Partial evidence “At LT Harper we specialise in cyber security, artificial intelligence, legal tech and tech transformation recruitment.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 17 contacts → | ||||
Indirect evidence “Exceptional Talent for Amazing Technology Companies.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 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. | |||||
| 14 | 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. | |||||
| 15 | 15 contacts → | ||||
Indirect evidence “Who We Are DataSixth delivers Cybersecurity Intelligence.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 13 contacts → | ||||
Indirect evidence “At Mentmore we understand that hiring exceptional people is important for our clients but that it is only one part of their job.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 13 contacts → | ||||
Partial evidence “Secure On Site was founded to provide high-quality, skilled SIA licensed security staff at a realistic price point.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 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. | |||||
| 19 | 12 contacts → | ||||
Partial evidence “Empowering enterprises to thrive through.expert staffing, strategic consultancy & innovative solutions.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 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. | |||||
| 21 | 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. | |||||
| 22 | 11 contacts → | ||||
Indirect evidence “We are on a mission to make people happier at work.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 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. | |||||
| 24 | 10 contacts → | ||||
Partial evidence “Hydras is a Digital & Cloud Transformation Consultancy that specialise in Cyber Security.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 25 | 10 contacts → | ||||
Partial 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, 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: security engineering staffing 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 security engineering staffing companies.
- Partial evidence
- Its own public description names part of security engineering staffing companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name security engineering staffing 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 189 security engineering staffing companies based in London, United Kingdom
See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 542 reachable decision-makers.
Free signup · no credit card
Security engineering staffing companies 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 189 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 security engineering staffing 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 “security engineering staffing 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 security engineering staffing 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 security engineering staffing 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, 542 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 security engineering staffing 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 security engineering staffing companies are there based in London, United Kingdom?
RevenueBase identified 189 security engineering staffing 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?
Computer Futures, headquartered in London, tops this list with the largest team on record.
Which city in the United Kingdom has the most security engineering staffing companies?
London leads the United Kingdom with 189 headquartered companies, followed by Manchester (28) and Birmingham (11).
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 542 verified decision-maker contacts tracked across these 189 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.
Ready to reach these companies? Verified emails and direct dials for all 189 security engineering staffing companies based in London, United Kingdom. Start with a free account, no credit card.
Download this list →Related lists
Security engineering staffing companies by geography
- Security engineering staffing companies based in Melbourne, Australia
- Security engineering staffing companies based in Sydney, Australia
- Security engineering staffing companies based in Sao Paulo, Brazil
- Security engineering staffing companies based in Ottawa, Canada
- Security engineering staffing companies based in Toronto, Canada
- Security engineering staffing companies based in Paris, France
- Security engineering staffing companies based in Ahmedabad, India
- Security engineering staffing companies based in Bangalore, India
- Security engineering staffing companies based in Chennai, India
- Security engineering staffing companies based in Hyderabad, India
- Security engineering staffing companies based in Pune, India
- Security engineering staffing companies based in Amsterdam, Netherlands
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.
More company lists
- All company lists
- Lists by location
- Lists A-Z
- New lists
- Security engineering staffing companies based in Melbourne, Australia
- Security engineering staffing companies based in Sydney, Australia
- Security engineering staffing companies based in Sao Paulo, Brazil
- Security engineering staffing companies based in Ottawa, Canada
- Security engineering staffing companies based in Toronto, Canada
- Security engineering staffing companies based in Paris, France