Company lists · Data refreshed September 2026
Top 25 Top 10 security companies based in London, United Kingdom
RevenueBase identified 463 company matches for top 10 security companies associated with London, United Kingdom as of September 2026 and tracks 85,570 professional contacts across them, including 1,309 with verified work emails. Across the United Kingdom, London is the largest hub for this category.
This list covers company matches for top 10 security companies associated with London, United Kingdom, found by RevenueBase SmartSearch using the meaning of business descriptions in its company graph at Exact. Ranked by professionals tracked, largest first. Rows show recorded descriptions where available, Exact search membership and the snapshot date. Data refreshed September 21, 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.
The 25 largest top 10 security companies based in London, United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 79,699 contacts → | ||||
Exact match “G4S is a leading security and facility services company that provides proactive security services and cutting-edge smart technology to deliver tailored, integrated security…” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 2 | 919 contacts → | ||||
Exact match “CIS Security is an independent security company equipped to help customers to solve the complex challenges in today’s digital, connected and regulated business world.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 3 | 242 contacts → | ||||
Exact match “Obrela Security Industries is a global provider of cyber security services.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 4 | 105 contacts → | ||||
Exact match “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.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 5 | 97 contacts → | ||||
Exact match “As an independent IT security specialist, Caretower provide comprehensive solutions to individual problems, thus allowing our recommendations to be unbiased.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 6 | 87 contacts → | ||||
Exact match “ITC Secure is an advisory-led cyber security services company.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 7 | 64 contacts → | ||||
Exact match “City Security Services (CSS) have more than 25 years’ experience within the corporate security, public sector, education and social housing markets delivering manned guarding…” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 8 | 58 contacts → | ||||
Exact match “Assist Security Group (ASG) helps clients build resilient, comprehensive security strategies that protect their people and assets, business continuity and reputation.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 9 | 58 contacts → | ||||
Exact match “Black Diamond Security - Safeguarding Your World.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 10 | 52 contacts → | ||||
Exact match “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…” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 11 | 51 contacts → | ||||
Exact match “Established in Custom Intelligent Security is a technology driven ISO27001 & NSi Gold Accredited independent electronic security specialist with a proven track record of…” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 12 | 48 contacts → | ||||
Exact match “In today’s complex threat environment, businesses, individuals, and organisations require trusted partners to provide the ultimate assurance that their assets are well protected.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 13 | 44 contacts → | ||||
Exact match “CornerStone is an award winning, independent, security and digital building consulting firm with headquarters in the UK.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 14 | 43 contacts → | ||||
Exact match “AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 15 | 39 contacts → | ||||
Exact match “Gratte Brothers is an experienced provider of integrated security solutions, which are Built on Strong Values and ultimately deliver a measurable return on investment.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 16 | 36 contacts → | ||||
Exact match “Harod Associates delivers global investigation and security solutions to complex crime and risk issues.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 17 | 34 contacts → | ||||
Exact match “Our elite teams offer bespoke, integrated security solutions that adapt and react to the evolving threat landscape.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 18 | 32 contacts → | ||||
Exact match “CYB3R Group, is a leading provider of comprehensive Cyber Security, IT and Communications Solutions.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 19 | 30 contacts → | ||||
Exact match “Capstar provides technology-enabled threat, risk and security services to private and corporate clients.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 20 | 29 contacts → | ||||
Exact match “Cyber security is the modern business' greatest risk.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 21 | 28 contacts → | ||||
Exact match “Priavo Security Group is an established provider of comprehensive security risk management, dedicated to safeguarding individuals, information, assets, and reputation through…” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 22 | 26 contacts → | ||||
Exact match “Our overarching aim is to safeguard your information so that you can focus on taking your business where you want it to go.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 23 | 24 contacts → | ||||
Exact match “Nanjgel Solutions is focused on delivering the best IT security for businesses.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 24 | 23 contacts → | ||||
Exact match “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…” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
| 25 | 22 contacts → | ||||
Exact match “Our Chartered Security Professionals seamlessly integrate discreet and effective security into lifestyles and organisations.” Recorded in the RevenueBase company graph · Sep 21, 2026 · View company records in RevenueBase | |||||
RevenueBase SmartSearch
Describe a niche business in your own words. RevenueBase SmartSearch compares the meaning of your description with company business descriptions compiled in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit.
This list uses Exact for “top 10 security companies”. Each Exact match badge shows membership in that saved search; it is not an individual similarity score or a service-quality rating. Recorded descriptions are shown where available.
Showing 25 of 463 top 10 security companies based in London, United Kingdom
See the full list, filter by size, metro and specialty, and access 1,309 tracked professional contacts with verified work emails. Direct dials are available where recorded.
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Top 10 security companies based in London, United Kingdom at a glance
As of Sep 21, 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 463 companies.
How this list was built
The recorded descriptions help you assess these company matches. Check a company’s website for its current services and locations.
- 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
- Company records associated with London, United Kingdom whose business descriptions match “top 10 security companies” by meaning at the Exact setting. Descriptions are compiled in the RevenueBase company graph from public websites, profiles and company information where available; they are not guaranteed quotations from the company's website.
- RevenueBase SmartSearch
- Describe a niche company in your own words to find businesses by meaning. Exact, Similar, Related and Broad control the breadth of RevenueBase SmartSearch. This saved list uses Exact. Each row's Exact match badge shows inclusion in that search, not an individual score or a service-quality judgment.
- Public preview
- The public preview omits records without a verified work email. Where headquarters information is recorded, preview rows are also filtered to this page’s location. Dataset totals and geographic summaries describe the full matched records before these preview filters.
- Match quality
- RevenueBase's August 25, 2026 study assessed 4,198 description/company pairs across matching settings. The publisher reports 86% good or better at Exact. This evaluates the method across queries; it does not audit this individual list. Recorded company descriptions, where available, help you judge each match yourself. Read the full methodology: how the lists are built and what the study measures.
- 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 displayed company carries at least one verified work email. RevenueBase tracks 1,309 professional contacts with verified work emails across the full matched dataset. 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 21, 2026. Lists refresh periodically as the graph is re-checked.
- Record context
- Company records and descriptions can change. Check the company's website for its current services and locations.
Top 10 security companies by metro in the United Kingdom
Frequently asked
What is RevenueBase SmartSearch?
RevenueBase SmartSearch finds niche companies by the meaning of their business descriptions in the RevenueBase company graph. Exact, Similar, Related and Broad control how closely companies must fit your description. This list uses Exact for “top 10 security companies”; each Exact match badge shows search membership, not an individual similarity or quality score.
How many top 10 security companies are there based in London, United Kingdom?
RevenueBase identified 463 company matches for top 10 security companies associated with London, United Kingdom as of September 2026, using the meaning of business descriptions at Exact. This is the recorded matched set in the RevenueBase company graph.
What is the largest company on this list?
G4s tops the displayed preview by professional contacts tracked in RevenueBase. Recorded headquarters appear in the company rows.
Which city in the United Kingdom has the most top 10 security companies?
London leads the United Kingdom with 463 company records, followed by Manchester (43) and Birmingham (29).
How do I get contact information for these companies?
A free RevenueBase account lets you run this exact search and work limited free results with 500 credits to start. Upgrading provides access to the 1,309 professional contacts with verified work emails tracked across these 463 companies; direct dials are available where recorded.
How current is this list?
The list refreshes periodically as the company graph is re-checked. This page's figures were pulled on September 21, 2026.
Ready to reach these companies? Verified emails and direct dials for all 463 top 10 security companies based in London, United Kingdom. Start with a free account, no credit card.
Download this list →Related lists
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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.
More company lists
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- Lists by location
- Lists A-Z
- New lists
- Top 10 security companies based in Brisbane, Australia
- Top 10 security companies based in Melbourne, Australia
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Company intelligence · public preview
Top 25 top 10 security companies based in London, United Kingdom
Find companies in any niche.
Describe the businesses you want in your own words. RevenueBase SmartSearch matches company descriptions by meaning.
RevenueBase records 463 matching company records for top 10 security companies based in London, United Kingdom, with 85,570 tracked contacts and 1,309 verified work emails.
This public preview shows 25 selected records ordered by tracked contacts. RevenueBase SmartSearch finds company descriptions that match by meaning at Exact. Snapshot: September 21, 2026.
RevenueBase compiles business descriptions for niche-company discovery; each row shows a recorded excerpt where available. Adapt this search to find the companies and contacts you want.
Top 25 top 10 security companies based in London, United Kingdom
The public list shows selected company records with contact and verified-email coverage. Reported employee bands provide separate company-size context.
| # | Company | Headquarters on record | Reported employees | RevenueBase SmartSearch | Tracked contacts |
|---|---|---|---|---|---|
| 1 |  G4sg4s.comHQ: London, United KingdomReported employees: 10001+ | London, United Kingdom | 10001+ | Exact match | 79,699 contacts → |
“G4S is a leading security and facility services company that provides proactive security services and cutting-edge smart technology to deliver tailored, integrated security…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 2 |  CIS Security Limitedcis-security.co.ukHQ: London, United KingdomReported employees: 1,001-5,000 | London, United Kingdom | 1,001-5,000 | Exact match | 919 contacts → |
“CIS Security is an independent security company equipped to help customers to solve the complex challenges in today’s digital, connected and regulated business world.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 3 |  Obrelaobrela.comHQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 242 contacts → |
“Obrela Security Industries is a global provider of cyber security services.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 4 |  Conoscoconosco.comHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 105 contacts → |
“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.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 5 |  Caretower An Integrity360 Companyintegrity360.comHQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 97 contacts → |
“As an independent IT security specialist, Caretower provide comprehensive solutions to individual problems, thus allowing our recommendations to be unbiased.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 6 |  ITC Secureitcsecure.comHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 87 contacts → |
“ITC Secure is an advisory-led cyber security services company.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 7 |  City Security Services Part Of City Group Securitycitysecurity.org.ukHQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 64 contacts → |
“City Security Services (CSS) have more than 25 years’ experience within the corporate security, public sector, education and social housing markets delivering manned guarding…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 8 |  Assist Security Groupassistsecurity.co.ukHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 58 contacts → |
“Assist Security Group (ASG) helps clients build resilient, comprehensive security strategies that protect their people and assets, business continuity and reputation.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 9 |  Black Diamond Securityblackdiamondsecurity.co.ukHQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 58 contacts → |
“Black Diamond Security - Safeguarding Your World.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 10 |  Hexegichexegic.comHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 52 contacts → |
“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…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 11 |  Custom Intelligent Securitycustomsecurity.tvHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 51 contacts → |
“Established in Custom Intelligent Security is a technology driven ISO27001 & NSi Gold Accredited independent electronic security specialist with a proven track record of…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 12 |  Frankton Group LTDfranktongroup.comHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 48 contacts → |
“In today’s complex threat environment, businesses, individuals, and organisations require trusted partners to provide the ultimate assurance that their assets are well protected.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 13 |  Cornerstonecornerstonegrg.co.ukHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 44 contacts → |
“CornerStone is an award winning, independent, security and digital building consulting firm with headquarters in the UK.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 14 |  Ak9 Security And FM Solutions LTDak9security.comHQ: London, United KingdomReported employees: 501-1,000 | London, United Kingdom | 501-1,000 | Exact match | 43 contacts → |
“AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 15 | HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 39 contacts → |
“Gratte Brothers is an experienced provider of integrated security solutions, which are Built on Strong Values and ultimately deliver a measurable return on investment.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 16 |  HARODharodassociates.comHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 36 contacts → |
“Harod Associates delivers global investigation and security solutions to complex crime and risk issues.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 17 |  Team Fusion LTDteamfusion.comHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 34 contacts → |
“Our elite teams offer bespoke, integrated security solutions that adapt and react to the evolving threat landscape.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 18 |  Cyb3rcyb3rsolutrions.comHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 32 contacts → |
“CYB3R Group, is a leading provider of comprehensive Cyber Security, IT and Communications Solutions.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 19 |  Capstarcapstar.coHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 30 contacts → |
“Capstar provides technology-enabled threat, risk and security services to private and corporate clients.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 20 |  J2 Msspj2mssp.comHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 29 contacts → |
“Cyber security is the modern business' greatest risk.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 21 |  Priavo Securitypriavosecurity.comHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 28 contacts → |
“Priavo Security Group is an established provider of comprehensive security risk management, dedicated to safeguarding individuals, information, assets, and reputation through…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 22 |  Smartsafe Consulting And Technologysmartsafeuk.comHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 26 contacts → |
“Our overarching aim is to safeguard your information so that you can focus on taking your business where you want it to go.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 23 |  Nanjgel Solutionsnanjgel.comHQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 24 contacts → |
“Nanjgel Solutions is focused on delivering the best IT security for businesses.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 24 |  Toro Solutionstorosolutions.co.ukHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 23 contacts → |
“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…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 25 |  Kiris Groupkirisgroup.comHQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 22 contacts → |
“Our Chartered Security Professionals seamlessly integrate discreet and effective security into lifestyles and organisations.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
Showing 25 of 463 company matches
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Top 10 security companies: dataset insights
September 21, 2026These summaries describe recorded coverage in this saved dataset. This page is derived from saved source records; per-contact mobile coverage and email-recency results are not established by this snapshot.
Reported company sizes
462 records in the displayed employee bands.
1 matching records are outside the displayed bands or do not have a displayed size. Bars show shares of the displayed bands.
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 463 companies.
How this company list was built
Describe a niche in your own words: companies installing commercial solar, or manufacturers of sustainable packaging. RevenueBase SmartSearch finds companies whose compiled business descriptions match by meaning. This list is one saved example to adapt.
Where the company descriptions come from
RevenueBase compiles company information from public sources, including company websites and public professional profiles such as LinkedIn, alongside information supplied by companies. The short recorded excerpt shown here is separate from the complete business description used for matching; individual source URLs and collection dates are not provided in this public snapshot.
RevenueBase SmartSearch matching settings
- Exact
- Closest fits to the business described.
- Similar
- Similar businesses with a wider range of fits.
- Related
- Related businesses in and around the category.
- Broad
- A broader set of businesses connected to the description.
RevenueBase SmartSearch · Exact match identifies inclusion in this search's closest semantic matching setting. It is not a per-company confidence score, a literal keyword match, or a quality endorsement.
Selection, ordering and scope
The public list shows selected company records with contact and verified-email coverage. Reported employee bands provide separate company-size context.
This page is derived from saved source records; per-contact mobile coverage and email-recency results are not established by this snapshot.
Recorded company descriptions support research; check company websites for current services. The selected preview is ordered by tracked contacts and is not a list of the best service providers.
Snapshot: September 21, 2026.
RevenueBase is a B2B data infrastructure company. Its September 3, 2026 published methodology describes a graph of 60 million companies and 398.9 million professional contacts; these platform figures differ from this page's totals. Published methodology ↗
Top 10 security companies by metro in the United Kingdom
Questions about this company list
What does Exact match mean for top 10 security companies?
The separate RevenueBase SmartSearch column identifies inclusion at the closest semantic matching preset. It is not a literal keyword match, a per-company confidence score or a quality endorsement. Changing the search form opens a new search in RevenueBase; it does not reclassify these saved rows.
How many top 10 security companies did RevenueBase find based in London, United Kingdom?
The saved snapshot records 463 matching company records, 85,570 tracked contacts and 1,309 verified emails. The public preview displays 25 selected records.
Where do the company descriptions come from?
RevenueBase compiles company information from public sources, including company websites and public professional profiles such as LinkedIn, alongside information supplied by companies. The short recorded excerpt shown here is separate from the complete business description used for matching; individual source URLs and collection dates are not provided in this public snapshot.
How are the public companies ordered?
The selected public records are ordered by contacts tracked in RevenueBase, highest first. Contact coverage is a prospecting measure, not an assessment of the company's services or quality.
How can I get contact information?
Select a company's contact count to open its filtered contacts in RevenueBase. Free signup is required and includes 500 credits and limited free results. Verified emails, direct dials and mobile numbers depend on available coverage.
How current is this list?
Snapshot: September 21, 2026. Review each company's website for current services and locations. A recorded business description does not establish that every company offers every service named in the search.
What do headquarters and employee bands mean?
These are recorded company-level fields, rather than a map of every branch or a count of specialists. Missing headquarters or employee bands are labeled; older records may show a location separately from recorded headquarters.
Build your next target company list
Adapt this niche search and work with available contacts in RevenueBase.
Related lists
Top 10 security companies by geography
- Top 10 security companies based in Brisbane, Australia
- Top 10 security companies based in Melbourne, Australia
- Top 10 security companies based in Sydney, Australia
- Top 10 security companies based in Belo Horizonte, Brazil
- Top 10 security companies based in Porto Alegre, Brazil
- Top 10 security companies based in Rio De Janeiro, Brazil
- Top 10 security companies based in Sao Paulo, Brazil
- Top 10 security companies based in Calgary, Canada
- Top 10 security companies based in Edmonton, Canada
- Top 10 security companies based in Mississauga, Canada
- Top 10 security companies based in Montreal, Canada
- Top 10 security companies based in Ottawa, Canada
Cite this list
RevenueBase Data Team. Top 25 top 10 security companies based in London, United Kingdom. Snapshot: September 21, 2026. https://revenuebase.ai/companies/top-10-security-companies/united-kingdom/london.
This is a selected public preview of saved company records, rather than an independently verified census. Open the source page ↗
More company lists
- All company lists
- Lists by location
- Lists A-Z
- New lists
- Top 10 security companies based in Brisbane, Australia
- Top 10 security companies based in Melbourne, Australia
- Top 10 security companies based in Sydney, Australia
- Top 10 security companies based in Belo Horizonte, Brazil
- Top 10 security companies based in Porto Alegre, Brazil
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Company intelligence · public preview
Top 25 top 10 security companies based in London, United Kingdom
RevenueBase records 463 matching company records for top 10 security companies based in London, United Kingdom, with 85,570 tracked contacts and 1,309 verified work emails.
This public preview shows 25 selected records ordered by tracked contacts. RevenueBase SmartSearch finds company descriptions that match by meaning at Exact. Snapshot: September 21, 2026.
RevenueBase compiles business descriptions for niche-company discovery; each row shows a recorded excerpt where available. Adapt this search to find the companies and contacts you want.
Top 25 top 10 security companies based in London, United Kingdom
The public list shows selected company records with contact and verified-email coverage. Reported employee bands provide separate company-size context.
| # | Company | Headquarters on record | Reported employees | RevenueBase SmartSearch | Tracked contacts |
|---|---|---|---|---|---|
| 1 | G4sg4s.com HQ: London, United KingdomReported employees: 10001+ | London, United Kingdom | 10001+ | Exact match | 79,699 contacts → |
“G4S is a leading security and facility services company that provides proactive security services and cutting-edge smart technology to deliver tailored, integrated security…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 2 | CIS Security Limitedcis-security.co.uk HQ: London, United KingdomReported employees: 1,001-5,000 | London, United Kingdom | 1,001-5,000 | Exact match | 919 contacts → |
“CIS Security is an independent security company equipped to help customers to solve the complex challenges in today’s digital, connected and regulated business world.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 3 | Obrelaobrela.com HQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 242 contacts → |
“Obrela Security Industries is a global provider of cyber security services.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 4 | Conoscoconosco.com HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 105 contacts → |
“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.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 5 | Caretower An Integrity360 Companyintegrity360.com HQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 97 contacts → |
“As an independent IT security specialist, Caretower provide comprehensive solutions to individual problems, thus allowing our recommendations to be unbiased.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 6 | ITC Secureitcsecure.com HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 87 contacts → |
“ITC Secure is an advisory-led cyber security services company.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 7 | City Security Services Part Of City Group Securitycitysecurity.org.uk HQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 64 contacts → |
“City Security Services (CSS) have more than 25 years’ experience within the corporate security, public sector, education and social housing markets delivering manned guarding…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 8 | Assist Security Groupassistsecurity.co.uk HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 58 contacts → |
“Assist Security Group (ASG) helps clients build resilient, comprehensive security strategies that protect their people and assets, business continuity and reputation.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 9 | Black Diamond Securityblackdiamondsecurity.co.uk HQ: London, United KingdomReported employees: 201-500 | London, United Kingdom | 201-500 | Exact match | 58 contacts → |
“Black Diamond Security - Safeguarding Your World.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 10 | Hexegichexegic.com HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 52 contacts → |
“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…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 11 | Custom Intelligent Securitycustomsecurity.tv HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 51 contacts → |
“Established in Custom Intelligent Security is a technology driven ISO27001 & NSi Gold Accredited independent electronic security specialist with a proven track record of…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 12 | Frankton Group LTDfranktongroup.com HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 48 contacts → |
“In today’s complex threat environment, businesses, individuals, and organisations require trusted partners to provide the ultimate assurance that their assets are well protected.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 13 | Cornerstonecornerstonegrg.co.uk HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 44 contacts → |
“CornerStone is an award winning, independent, security and digital building consulting firm with headquarters in the UK.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 14 | Ak9 Security And FM Solutions LTDak9security.com HQ: London, United KingdomReported employees: 501-1,000 | London, United Kingdom | 501-1,000 | Exact match | 43 contacts → |
“AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 15 | HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 39 contacts → |
“Gratte Brothers is an experienced provider of integrated security solutions, which are Built on Strong Values and ultimately deliver a measurable return on investment.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 16 | HARODharodassociates.com HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 36 contacts → |
“Harod Associates delivers global investigation and security solutions to complex crime and risk issues.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 17 | Team Fusion LTDteamfusion.com HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 34 contacts → |
“Our elite teams offer bespoke, integrated security solutions that adapt and react to the evolving threat landscape.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 18 | Cyb3rcyb3rsolutrions.com HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 32 contacts → |
“CYB3R Group, is a leading provider of comprehensive Cyber Security, IT and Communications Solutions.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 19 | Capstarcapstar.co HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 30 contacts → |
“Capstar provides technology-enabled threat, risk and security services to private and corporate clients.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 20 | J2 Msspj2mssp.com HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 29 contacts → |
“Cyber security is the modern business' greatest risk.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 21 | Priavo Securitypriavosecurity.com HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 28 contacts → |
“Priavo Security Group is an established provider of comprehensive security risk management, dedicated to safeguarding individuals, information, assets, and reputation through…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 22 | Smartsafe Consulting And Technologysmartsafeuk.com HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 26 contacts → |
“Our overarching aim is to safeguard your information so that you can focus on taking your business where you want it to go.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 23 | Nanjgel Solutionsnanjgel.com HQ: London, United KingdomReported employees: 51-200 | London, United Kingdom | 51-200 | Exact match | 24 contacts → |
“Nanjgel Solutions is focused on delivering the best IT security for businesses.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 24 | Toro Solutionstorosolutions.co.uk HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 23 contacts → |
“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…” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
| 25 | Kiris Groupkirisgroup.com HQ: London, United KingdomReported employees: 11-50 | London, United Kingdom | 11-50 | Exact match | 22 contacts → |
“Our Chartered Security Professionals seamlessly integrate discreet and effective security into lifestyles and organisations.” Recorded description excerpt · September 21, 2026Open company data in RevenueBase ↗Free signup required. | |||||
Showing 25 of 463 company matches
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Top 10 security companies: dataset insights
September 21, 2026These summaries describe recorded coverage in this saved dataset. This page is derived from saved source records; per-contact mobile coverage and email-recency results are not established by this snapshot.
Reported company sizes
462 records in the displayed employee bands.
1 matching records are outside the displayed bands or do not have a displayed size. Bars show shares of the displayed bands.
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 463 companies.
How this company list was built
Describe a niche in your own words: companies installing commercial solar, or manufacturers of sustainable packaging. RevenueBase SmartSearch finds companies whose compiled business descriptions match by meaning. This list is one saved example to adapt.
Where the company descriptions come from
RevenueBase compiles company information from public sources, including company websites and public professional profiles such as LinkedIn, alongside information supplied by companies. The short recorded excerpt shown here is separate from the complete business description used for matching; individual source URLs and collection dates are not provided in this public snapshot.
RevenueBase SmartSearch matching settings
- Exact
- Closest fits to the business described.
- Similar
- Similar businesses with a wider range of fits.
- Related
- Related businesses in and around the category.
- Broad
- A broader set of businesses connected to the description.
RevenueBase SmartSearch · Exact match identifies inclusion in this search's closest semantic matching setting. It is not a per-company confidence score, a literal keyword match, or a quality endorsement.
Selection, ordering and scope
The public list shows selected company records with contact and verified-email coverage. Reported employee bands provide separate company-size context.
This page is derived from saved source records; per-contact mobile coverage and email-recency results are not established by this snapshot.
Recorded company descriptions support research; check company websites for current services. The selected preview is ordered by tracked contacts and is not a list of the best service providers.
Snapshot: September 21, 2026.
RevenueBase is a B2B data infrastructure company. Its September 3, 2026 published methodology describes a graph of 60 million companies and 398.9 million professional contacts; these platform figures differ from this page's totals. Published methodology ↗
Top 10 security companies by metro in the United Kingdom
Questions about this company list
What does Exact match mean for top 10 security companies?
The separate RevenueBase SmartSearch column identifies inclusion at the closest semantic matching preset. It is not a literal keyword match, a per-company confidence score or a quality endorsement. Changing the search form opens a new search in RevenueBase; it does not reclassify these saved rows.
How many top 10 security companies did RevenueBase find based in London, United Kingdom?
The saved snapshot records 463 matching company records, 85,570 tracked contacts and 1,309 verified emails. The public preview displays 25 selected records.
Where do the company descriptions come from?
RevenueBase compiles company information from public sources, including company websites and public professional profiles such as LinkedIn, alongside information supplied by companies. The short recorded excerpt shown here is separate from the complete business description used for matching; individual source URLs and collection dates are not provided in this public snapshot.
How are the public companies ordered?
The selected public records are ordered by contacts tracked in RevenueBase, highest first. Contact coverage is a prospecting measure, not an assessment of the company's services or quality.
How can I get contact information?
Select a company's contact count to open its filtered contacts in RevenueBase. Free signup is required and includes 500 credits and limited free results. Verified emails, direct dials and mobile numbers depend on available coverage.
How current is this list?
Snapshot: September 21, 2026. Review each company's website for current services and locations. A recorded business description does not establish that every company offers every service named in the search.
What do headquarters and employee bands mean?
These are recorded company-level fields, rather than a map of every branch or a count of specialists. Missing headquarters or employee bands are labeled; older records may show a location separately from recorded headquarters.
Build your next target company list
Adapt this niche search and work with available contacts in RevenueBase.
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Cite this list
RevenueBase Data Team. Top 25 top 10 security companies based in London, United Kingdom. Snapshot: September 21, 2026. https://revenuebase.ai/companies/top-10-security-companies/united-kingdom/london.
This is a selected public preview of saved company records, rather than an independently verified census. Open the source page ↗
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