Company lists · Data refreshed September 2026

Top 25 Investigative research firms based in the United Kingdom

Name: Investigative research firms based in the United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 20, 2026 221 companies tracked

RevenueBase identified 221 investigative research firms headquartered in the United Kingdom as of September 2026 and tracks 1,811 professional contacts across them, including 416 with verified work emails. London is the largest hub.

This list covers investigative research firms 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, its RevenueBase Smart Search rating, and when it was last checked. Data refreshed September 20, 2026.

Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.

How to read this list HQ checked on every row RevenueBase Smart Search rating on every row Refreshed Sep 20, 2026 86% judged on-target in blind review

221Companies

1,811Contacts tracked

416Verified emails

Explore this list → Free signup · no credit card · 500 free credits

The 25 largest investigative research firms based in the United Kingdom

Ranked by team size

Top 25 of 221 investigative research firms based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 20, 2026. RevenueBase Smart Search rates how each company's information relates to investigative research firms: strong evidence (its own description names it), partial (names part of it), indirect (matched on the rest of its profile rather than the description shown). Click a contact count to view that company's people.
#	Company	RevenueBase Smart Search	Headquarters	Employees	Contacts
1	Colvill Banks LTD	Partial evidence	Fareham, United KingdomHQ checked Sep 20, 2026	201-500	309 contacts →
	Partial evidence “Colvill Banks are experts in candidate research and identification.” Source: RevenueBase Database · checked Sep 20, 2026
2	Neotas	Indirect evidence	London, United KingdomHQ checked Sep 20, 2026	51-200	159 contacts →
	Indirect evidence “By leveraging cutting-edge technology and experienced analysts, Neotas are going beyond and setting new standards in Due Diligence, Staff Screening, and Compliance.” Source: RevenueBase Database · checked Sep 20, 2026
3	Corporate Research And Investigations	Strong evidence	London, United KingdomHQ checked Sep 20, 2026	51-200	140 contacts →
	Strong evidence “Corporate Research and Investigations Limited is a global provider of investigative research, background screening and business due diligence services for the world’s leading…” Source: RevenueBase Database · checked Sep 20, 2026
4	FACT	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	51-200	117 contacts →
	Partial evidence “FACT are at the forefront of investigative and intelligence services, recognised by organisations, law enforcement, and governments worldwide.” Source: RevenueBase Database · checked Sep 20, 2026
5	The Risk Advisory Group	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	51-200	94 contacts →
	Partial evidence “Risk Advisory Group is a global business intelligence and investigations firm.” Source: RevenueBase Database · checked Sep 20, 2026
6	Netwatch Global	Partial evidence	Birmingham, United KingdomHQ checked Sep 20, 2026	51-200	66 contacts →
	Partial evidence “NetWatch Global® specialise in online investigations and are experts in social media and open source investigation.” Source: RevenueBase Database · checked Sep 20, 2026
7	Examworks Investigation Services	Partial evidence	Bolton, United KingdomHQ checked Sep 20, 2026	51-200	51 contacts →
	Partial evidence “ExamWorks Investigation Services is a leading claims investigation company providing the insurance, banking, retail and other sectors with a range of innovative and cost effective…” Source: RevenueBase Database · checked Sep 20, 2026
8	ICP	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	51-200	38 contacts →
	Partial evidence “ICP is an independent, human-led research firm providing decision-grade intelligence on companies operating in markets where reliable data cannot be trusted.” Source: RevenueBase Database · checked Sep 20, 2026
9	HAROD	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	11-50	36 contacts →
	Partial evidence “Harod Associates delivers global investigation and security solutions to complex crime and risk issues.” Source: RevenueBase Database · checked Sep 20, 2026
10	Venovox	Indirect evidence	London, United KingdomHQ checked Sep 20, 2026	51-200	35 contacts →
	Indirect evidence “At VENOVOX, we are a premier consultancy in risk management and background screening, delivering specialised services in due diligence, security advisory, background checks, and…” Source: RevenueBase Database · checked Sep 20, 2026
11	RGI	Partial evidence	Cheadle Hulme, United KingdomHQ checked Sep 20, 2026	51-200	30 contacts →
	Partial evidence “RGI Solutions - Solving the Toughest Cases with Precision and Expertise Welcome to RGI Solutions, the leading independent investigations company in the UK!” Source: RevenueBase Database · checked Sep 20, 2026
12	Sastre Consulting	Strong evidence	London, United KingdomHQ checked Sep 20, 2026	11-50	23 contacts →
	Strong evidence “Sastre is a research consultancy, a global collective of multi-lingual corporate investigations professionals and public policy analysts who specialise in modern open source…” Source: RevenueBase Database · checked Sep 20, 2026
13	Kiris Group	Indirect evidence	London, United KingdomHQ checked Sep 20, 2026	11-50	22 contacts →
	Indirect evidence “Our Chartered Security Professionals seamlessly integrate discreet and effective security into lifestyles and organisations.” Source: RevenueBase Database · checked Sep 20, 2026
14	Tenintelligence	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	11-50	19 contacts →
	Partial evidence “Our continued vision is to be the playmaker in our field; an investigation and protection consultancy, recognised for our diligence, excellence & integrity.” Source: RevenueBase Database · checked Sep 20, 2026
15	Diligence	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	51-200	18 contacts →
	Partial evidence “Diligence is a private investigations firm, the output of our investigations help our clients make informed decisions bridging the gap between what they know and what they need to…” Source: RevenueBase Database · checked Sep 20, 2026
16	Hartford Advisers	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	11-50	15 contacts →
	Partial evidence “Hartford Advisers is a specialist intelligence, research and due diligence firm.” Source: RevenueBase Database · checked Sep 20, 2026
17	Quest Sports Investigations, Intelligence, Security	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	11-50	10 contacts →
	Partial evidence “Quest provides bespoke investigations, integrity and security services to corporate clients, sports organisations, and high net worth individuals.” Source: RevenueBase Database · checked Sep 20, 2026
18	CRI	Indirect evidence	Grays Inn, United KingdomHQ checked Sep 20, 2026	1-10	10 contacts →
	Indirect evidence “CRI is an intelligence and advisory firm based in London and New York.” Source: RevenueBase Database · checked Sep 20, 2026
19	Silverbridge	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	1-10	9 contacts →
	Partial evidence “Silverbridge is an independent investigations and intelligence firm offering a full range of information gathering services.” Source: RevenueBase Database · checked Sep 20, 2026
20	National Milk Laboratories Limited	Indirect evidence	Glasgow, United KingdomHQ checked Sep 20, 2026	11-50	9 contacts →
	Indirect evidence Source: RevenueBase Database · checked Sep 20, 2026
21	Garancie Limited	Indirect evidence	Sevenoaks, United KingdomHQ checked Sep 20, 2026	1-10	8 contacts →
	Indirect evidence “GARANCIE is an independent company specialising in public record searches and Enhanced Due Diligence.” Source: RevenueBase Database · checked Sep 20, 2026
22	Insightx	Partial evidence	London, United KingdomHQ checked Sep 20, 2026	1-10	8 contacts →
	Partial evidence “InsightX is a specialist independent intelligence, investigations and due diligence agency.” Source: RevenueBase Database · checked Sep 20, 2026
23	Intelligentsia Worldwide	Indirect evidence	London, United KingdomHQ checked Sep 20, 2026	11-50	8 contacts →
	Indirect evidence “Are You Looking For Competitive/Market Intelligence or Commercial Due Diligence Expertise?” Source: RevenueBase Database · checked Sep 20, 2026
24	Investigation Limited	Partial evidence	Newark, United KingdomHQ checked Sep 20, 2026	11-50	8 contacts →
	Partial evidence “Investigation Limited is a well-established company offering Corporate Intelligence Services globally.” Source: RevenueBase Database · checked Sep 20, 2026
25	Intraorbis Limited	Indirect evidence	Sudbury, United KingdomHQ checked Sep 20, 2026	1-10	7 contacts →
	Indirect evidence “IntraOrbis was founded in 2004 and quickly established itself within the Brand Protection sector as an international solution provider.” Source: RevenueBase Database · checked Sep 20, 2026

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: investigative research firms. 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 investigative research firms.
Partial evidence: Its own public description names part of investigative research firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name investigative research firms. 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 221 investigative research firms based in the United Kingdom

See the full list, filter by size, metro and specialty, and get verified emails and direct dials for all 416 reachable decision-makers.

Free signup · no credit card

View the full list →

Investigative research firms based in the United Kingdom at a glance

As of Sep 20, 2026

23.0%Verified-email coverage

8.2Average contacts per company

1-10Median size (employees)

38.9%Largest-city concentration · London

Sep 20, 2026Page data refreshed

Companies by employee count

1-10

152

11-50

51-200

201-500

Email recency for this list is measured worldwide rather than for United Kingdom, so it is reported there. Company counts and contact totals on this page are exact for United Kingdom, over 221 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 investigative research firms, 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 the United Kingdom whose own description of what they do matches “investigative research firms”. 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 investigative research firms), 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 investigative research firms, 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 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, 416 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 20, 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.

Investigative research firms by metro

Investigative research firms in London86

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 investigative research firms, 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 investigative research firms are there based in the United Kingdom?

RevenueBase identified 221 investigative research firms 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?

Colvill Banks LTD, headquartered in Fareham, tops this list with the largest team on record.

Which city has the most investigative research firms?

London leads with 86 headquartered companies, followed by Manchester (6) and Birmingham (4).

How do I get contact information for these companies?

A free RevenueBase account lets you run this exact search and work the top results, verified emails and direct dials included. Upgrading unlocks all 416 verified decision-maker contacts tracked across these 221 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 20, 2026.

Ready to reach these companies? Verified emails and direct dials for all 221 investigative research firms based in the United Kingdom. Start with a free account, no credit card.

Download this list →

Related lists

Investigative research firms by geography

Browse the directory

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.