Company lists · Data refreshed September 2026

Top 23 Oil and gas security companies based in London, United Kingdom

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

Compiled by the RevenueBase Data Team Data refreshed Sep 5, 2026 286 companies tracked

RevenueBase identified 286 oil and gas security companies headquartered in London, United Kingdom as of September 2026 and tracks 84,081 professional contacts across them, including 912 with verified work emails. London is the largest hub.

This list covers oil and gas security companies headquartered in London, United Kingdom, matched on what each company actually does as described in its own words. Ranked by team size, largest first. Every row shows the company's own description, 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

286Companies

84,081Contacts tracked

912Verified emails

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The 23 largest oil and gas security companies based in London, United Kingdom

Ranked by team size

Top 23 of 286 oil and gas security companies 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 oil and gas security companies: 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	G4sPartial evidence	London, United KingdomHQ checked Sep 5, 2026	10001+	79,699
	“G4S is a leading security and facility services company that provides proactive security services and cutting-edge smart technology to deliver tailored, integrated security…” Source: company website · checked Sep 5, 2026
2	CIS Security LimitedPartial evidence	London, United KingdomHQ checked Sep 5, 2026	1,001-5,000	919
	“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.” Source: company website · checked Sep 5, 2026
3	Ward SecurityPartial evidence	London, United KingdomHQ checked Sep 5, 2026	1,001-5,000	419
	“Ward is an award winning, privately owned business, providing bespoke risk and security solutions including protective security personnel, explosive search dogs, narcotic search…” Source: company website · checked Sep 5, 2026
4	QCICPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	159
	“QCIC is an award-winning global engineering firm specialising in designing, building and running security systems.” Source: company website · checked Sep 5, 2026
5	The Keyholding CompanyPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	137
	“The Keyholding Company are a tech-enabled mobile security services company, specialising in alarm response, mobile patrols, locks and unlocks, emergency and temporary guarding…” Source: company website · checked Sep 5, 2026
6	Hobark International LimitedIndirect evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	113
	“Hobark International Limited (HIL) is an Integrated Services Company whose subsidiaries: DrillPet International Limited (DIL), Uniterm Nigeria Limited (UNL), UltiProc Nigeria…” Source: company website · checked Sep 5, 2026
7	Servoca Secure Solutions LimitedPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	85
	“At Servoca Secure Solutions, we take great pride in delivering a multi-service security business; offering a range of complementary products and services to both the public and…” Source: company website · checked Sep 5, 2026
8	Lead Element Security GroupPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	75
	“We are Veteran Owned, Veteran Operated Security company based in London (HQ), with operation nationwide.” Source: company website · checked Sep 5, 2026
9	KK Security & FM LTDPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	71
	“KK Security was established in 2014 with the goal of keeping people safe.” Source: company website · checked Sep 5, 2026
10	City Security Services Part Of City Group SecurityPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	64
	“City Security Services (CSS) have more than 25 years’ experience within the corporate security, public sector, education and social housing markets delivering manned guarding…” Source: company website · checked Sep 5, 2026
11	Black Diamond SecurityPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	58
	“Black Diamond Security - Safeguarding Your World.” Source: company website · checked Sep 5, 2026
12	Custom Intelligent SecurityPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	51
	“Established in Custom Intelligent Security is a technology driven ISO27001 & NSi Gold Accredited independent electronic security specialist with a proven track record of…” Source: company website · checked Sep 5, 2026
13	UK Protection LTDPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	45
	“UK Protection is widely recognised as the premier supplier of security solutions to the Corporate, Jewellery and Luxury Retail industries across the UK.” Source: company website · checked Sep 5, 2026
14	Ak9 Security And FM Solutions LTDPartial evidence	London, United KingdomHQ checked Sep 5, 2026	501-1,000	43
	“AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.” Source: company website · checked Sep 5, 2026
15	Gratte Brothers Security Systems & SoftwarePartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	39
	“Gratte Brothers is an experienced provider of integrated security solutions, which are Built on Strong Values and ultimately deliver a measurable return on investment.” Source: company website · checked Sep 5, 2026
16	BML GroupPartial evidence	London, United KingdomHQ checked Sep 5, 2026	11-50	37
	“Founded in 2015, BML Group is one of the UK's leading Security & Facilities Management providers, delivering tailored solutions that enhance operational efficiency and safety.” Source: company website · checked Sep 5, 2026
17	Team Fusion LTDPartial evidence	London, United KingdomHQ checked Sep 5, 2026	11-50	34
	“Our elite teams offer bespoke, integrated security solutions that adapt and react to the evolving threat landscape.” Source: company website · checked Sep 5, 2026
18	CapstarPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	30
	“Capstar provides technology-enabled threat, risk and security services to private and corporate clients.” Source: company website · checked Sep 5, 2026
19	Priavo SecurityPartial evidence	London, United KingdomHQ checked Sep 5, 2026	11-50	28
	“Priavo Security Group is an established provider of comprehensive security risk management, dedicated to safeguarding individuals, information, assets, and reputation through…” Source: company website · checked Sep 5, 2026
20	The Portmarnock GroupPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	19
	“The Portmarnock Group was built from years of experience, hard work and a genuine passion for doing security differently.” Source: company website · checked Sep 5, 2026
21	Line Security Services LTDPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	17
	“As a security services provider, protecting people and assets is our top priority.” Source: company website · checked Sep 5, 2026
22	SSG Support Services Group LTDPartial evidence	London, United KingdomHQ checked Sep 5, 2026	201-500	16
	“SSG Support Services Group LTD is specialists in provision of Manned guarding Security Services, Door Supervision, Security Guarding, Out of Hours Support, Concierge, Front of…” Source: company website · checked Sep 5, 2026
23	Integrated Visual Protection LimitedPartial evidence	London, United KingdomHQ checked Sep 5, 2026	51-200	16
	“Integrated Visual Protection Limited (IVP) is a privately owned Company, which has been established since 2002, providing all types of Fire and Security Services to a variety of…” Source: company website · checked Sep 5, 2026

Showing 23 of 286 oil and gas security companies based in London, United Kingdom

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Oil and gas security companies based in London, United Kingdom at a glance

As of Sep 5, 2026

11-50Median size (employees)

LondonLargest hub · 286 HQs

Contacts with mobile numbers

Sep 5, 2026Data refreshed

Companies by employee count

1-10

11-50

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 286 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 oil and gas security companies, 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 “oil and gas security companies”. 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 oil and gas security companies, and records with no verified work email. Companies headquartered outside London are excluded even when they keep an office there.
Match quality: In blind human judging of this matching method, 86% of matched companies were on target. Expect roughly 1 in 7 rows to be adjacent to the category rather than a pure play. Every row shows the company's own description and 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, 912 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.

Oil and gas security companies by metro in the United Kingdom

Oil and gas security companies in London286
Oil and gas security companies in Birmingham31
Oil and gas security companies in Manchester27

Frequently asked

How many oil and gas security companies are there based in London, United Kingdom?

RevenueBase identified 286 oil and gas security companies headquartered in London, United Kingdom as of September 2026, matched on each company's own description of what it does rather than its industry code.

What is the largest company on this list?

G4s, headquartered in London, tops this list with the largest team on record.

Which city has the most oil and gas security companies?

London leads with 286 headquartered companies, followed by Birmingham (31) and Manchester (27).

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 912 verified decision-maker contacts tracked across these 286 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.