Company lists · Data refreshed September 2026

Top 25 Government contract security companies based in the United Kingdom

RevenueBase identified 266 government contract security companies headquartered in the United Kingdom as of September 2026 and tracks 3,436 professional contacts across them, including 293 with verified work emails and 181 with mobile numbers. London is the largest hub.

This list covers government contract security companies headquartered in the 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 3, 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 3, 2026 86% judged on-target in blind review
266Companies
3,436Contacts tracked
293Verified emails
181Mobile numbers
Explore all 266 companies → Free signup · no credit card · 500 free credits

The 25 largest government contract security companies based in the United Kingdom

Ranked by team size
Top 25 of 266 government contract security companies based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 3, 2026. Evidence rates how directly each company's own description names government contract 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.
#CompanyHeadquartersEmployeesContacts
1
Regency SecurityPartial evidence
Braintree, United KingdomHQ checked Sep 3, 20261,001-5,000325

“Established in 1993, with commitment to our customers and staff alongside a strong ethos and standards driven approach, Regency Security is now the largest provider of door…”

Source: company website · checked Sep 3, 2026
2
Vespasian SecurityPartial evidence
Portsmouth, United KingdomHQ checked Sep 3, 2026201-500125

“Vespasian Security was formed in February 2006.”

Source: company website · checked Sep 3, 2026
3
Kingdom Security ServicesPartial evidence
Newton-Le-Willows, United KingdomHQ checked Sep 3, 20265,001-10,000124

“About Kingdom Security Established in March 1993, Kingdom Security is a leading UK security provider delivering professional, fully licensed security services nationwide.”

Source: company website · checked Sep 3, 2026
4
Octavian SecurityPartial evidence
Bingham, United KingdomHQ checked Sep 3, 2026201-50091

“The multi award winning Octavian is one of the world's fastest growing, most forward thinking security and facilities management led businesses.”

Source: company website · checked Sep 3, 2026
5
K4 Security - K4 GroupPartial evidence
Hounslow, United KingdomHQ checked Sep 3, 2026201-50090

“For a better service and competitive price try K4 Security Services At K4 we offer the following: 1.”

Source: company website · checked Sep 3, 2026
6London, United KingdomHQ checked Sep 3, 202651-20085

“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 3, 2026
7
Northern Security LTDPartial evidence
Carlisle, United KingdomHQ checked Sep 3, 2026201-50070

“Northern Security Ltd is a leading guarding, alarm response and electronic security business operating throughout the North of England and South West Scotland.”

Source: company website · checked Sep 3, 2026
8London, United KingdomHQ checked Sep 3, 2026201-50064

“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 3, 2026
9
Black Diamond SecurityPartial evidence
London, United KingdomHQ checked Sep 3, 2026201-50062

“Black Diamond Security - Safeguarding Your World.”

Source: company website · checked Sep 3, 2026
10
Sentinel Group SecurityPartial evidence
Loughton, United KingdomHQ checked Sep 3, 2026201-50058

“Sentinel Group Security is a fast growing provider of all aspects of security personnel and manned security services operating across the United Kingdom.”

Source: company website · checked Sep 3, 2026
11
Phoenix FMSPartial evidence
Newcastle Upon Tyne, United KingdomHQ checked Sep 3, 2026201-50044

“Design, install and maintain CCTV Systems Intruder Systems Access Control Manned Security Guarding Event Stewarding Construction Cleaning Commercial Cleaning Builders & Sparkle…”

Source: company website · checked Sep 3, 2026
12
AIB GroupPartial evidence
Park Bletchley, United KingdomHQ checked Sep 3, 2026201-50043

“All in Black are an accredited security solutions provider with over 20 years’ experience at the highest level across the UK.”

Source: company website · checked Sep 3, 2026
13London, United KingdomHQ checked Sep 3, 2026501-1,00043

“AK9 Security and FM Solutions offers comprehensive security solutions for businesses, governmental organizations, and residential areas.”

Source: company website · checked Sep 3, 2026
14
4 Site SecurityPartial evidence
Leeds, United KingdomHQ checked Sep 3, 202651-20040

“4 Site Security have specialised in providing professional security services to clients throughout the North of England for over 23 Years.”

Source: company website · checked Sep 3, 2026
15Manchester, United KingdomHQ checked Sep 3, 2026201-50033

“At Leisure Guard Security, we provide a wide range of security services to private individuals and corporate businesses alike.”

Source: company website · checked Sep 3, 2026
16Ilford, United KingdomHQ checked Sep 3, 2026201-50032

“Oak Security Services was founded in July 2015 and is now one of the fastest growing security companies in the UK.”

Source: company website · checked Sep 3, 2026
17
Prosec UKPartial evidence
Doncaster, United KingdomHQ checked Sep 3, 202651-20032

Security Specialists A discreet, reliable and effective service Providing highly trained professional security guards and associated round the clock security services and for over…”

Source: company website · checked Sep 3, 2026
18Liverpool, United KingdomHQ checked Sep 3, 202651-20032

“At Samson Security Fire & Facilities, we provide integrated security, fire protection, and facilities management solutions designed to keep people, property, and operations safe…”

Source: company website · checked Sep 3, 2026
19
Herongrange Group LimitedIndirect evidence
Burton Upon Trent, United KingdomHQ checked Sep 3, 2026201-50031

“At Herongrange we pride ourselves in delivering our products and services to the highest possible standards.”

Source: company website · checked Sep 3, 2026
20
Systematic Security LTDPartial evidence
London, United KingdomHQ checked Sep 3, 2026201-50031

“Systematic Security deliver static manned guarding, mobile patrols, open and lock ups, keyholding and emergency response requirements as well as Vacant Property inspections to a…”

Source: company website · checked Sep 3, 2026
21
EboracumIndirect evidence
York, United KingdomHQ checked Sep 3, 2026201-50027

“Eboracum was founded in 2011 and established in York by local-lad and former North Yorkshire Police Constable Carl Nickson.”

Source: company website · checked Sep 3, 2026
22
Glevum SecurityPartial evidence
Gloucester, United KingdomHQ checked Sep 3, 202651-20025

“We deliver professional, accredited security services that protect people, property, and organisations across the UK.”

Source: company website · checked Sep 3, 2026
23Darlington, United KingdomHQ checked Sep 3, 202651-20024

“Close Protection Security is an industry-leading security company, established in 2017 and based in the North East of England, created by Glenn Bartlett.”

Source: company website · checked Sep 3, 2026
24Crawley, United KingdomHQ checked Sep 3, 202651-20021

“Classic Security was founded in 1947 by Fredrick Townsley - the father of our chairman and the grandfather of our MD.”

Source: company website · checked Sep 3, 2026
25Ilford, United KingdomHQ checked Sep 3, 202651-20020
Source: company website · checked Sep 3, 2026

Showing 25 of 266 government contract security companies based in the United Kingdom

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Government contract security companies based in the United Kingdom at a glance

As of Sep 3, 2026
11-50Median size (employees)
LondonLargest hub · 68 HQs
181Contacts with mobile numbers
Sep 3, 2026Data refreshed

Companies by employee count

1-10
62
11-50
79
51-200
80
201-500
35
501-1,000
2
1,001-5,000
2
5,001-10,000
1

Verified emails by last verification

0–30
0
31–60
33
61–90
168
90–180
90
180+
2

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 government contract 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 the United Kingdom whose own description of what they do matches “government contract 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 government contract security companies, and records with no verified work email. Companies headquartered outside United Kingdom 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, 293 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 3, 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.

Government contract security companies by metro

  • Government contract security companies in London68

Frequently asked

How many government contract security companies are there based in the United Kingdom?

RevenueBase identified 266 government contract security companies headquartered in the 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?

Regency Security, headquartered in Braintree, tops this list with the largest team on record.

Which city has the most government contract security companies?

London leads with 68 headquartered companies, followed by Manchester (12) and Birmingham (12).

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 293 verified decision-maker contacts tracked across these 266 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 3, 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.