Company lists · Data refreshed September 2026
Top 25 Due diligence firms based in the United Kingdom
RevenueBase identified 156 due diligence firms headquartered in the United Kingdom as of September 2026 and tracks 2,075 professional contacts across them, including 797 with verified work emails. London is the largest hub.
This list covers due diligence 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 19, 2026.
Published by RevenueBase, a B2B data infrastructure company. This list was built with RevenueBase Smart Search, the natural-language company search RevenueBase customers use to build their own targeted lists and unlock verified emails and direct dials at the companies on them. How these lists are built and judged.
The 25 largest due diligence firms based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 242 contacts → | ||||
Indirect evidence “We help our customers to do the right business in the right way.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 2 | 195 contacts → | ||||
Indirect evidence “Forensic Risk Alliance (FRA) is an international consultancy that combines forensic accounting and forensic technology expertise to position businesses for success with…” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 3 | 159 contacts → | ||||
Strong 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 19, 2026Thanks. The Data Team will review it. | |||||
| 4 | 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 19, 2026Thanks. The Data Team will review it. | |||||
| 5 | 117 contacts → | ||||
Indirect evidence “FACT are at the forefront of investigative and intelligence services, recognised by organisations, law enforcement, and governments worldwide.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 6 | 100 contacts → | ||||
Indirect evidence “At Verifile, we’re committed to helping ensure that every one of your employees is everything they claim to be.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 7 | 94 contacts → | ||||
Indirect evidence “Risk Advisory Group is a global business intelligence and investigations firm.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 8 | 58 contacts → | ||||
Indirect evidence “Aperio Intelligence is an independent, integrity risk consultancy headquartered in the City of London.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 9 | 51 contacts → | ||||
Indirect 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 19, 2026Thanks. The Data Team will review it. | |||||
| 10 | 38 contacts → | ||||
Indirect 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 19, 2026Thanks. The Data Team will review it. | |||||
| 11 | 36 contacts → | ||||
Indirect evidence “Harod Associates delivers global investigation and security solutions to complex crime and risk issues.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 12 | 35 contacts → | ||||
Strong 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 19, 2026Thanks. The Data Team will review it. | |||||
| 13 | 30 contacts → | ||||
Indirect 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 19, 2026Thanks. The Data Team will review it. | |||||
| 14 | 28 contacts → | ||||
Indirect evidence “Verita is the leading independent consultancy for regulated organisations in the UK.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 15 | 28 contacts → | ||||
Indirect evidence “PROCIUS | Employment screening experts We are one of the largest pre-employment screening agency in the UK.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 16 | 24 contacts → | ||||
Strong evidence “Ground Truth Intelligence is the global due diligence platform designed for an ever-changing world.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 17 | 22 contacts → | ||||
Indirect evidence “Our Chartered Security Professionals seamlessly integrate discreet and effective security into lifestyles and organisations.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 18 | 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 19, 2026Thanks. The Data Team will review it. | |||||
| 19 | 18 contacts → | ||||
Indirect evidence “We give our clients the confidence to identify opportunities, mitigate risks, tackle challenges and understand the landscapes they inhabit.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 20 | 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 19, 2026Thanks. The Data Team will review it. | |||||
| 21 | 15 contacts → | ||||
Indirect evidence “For over two decades, our trusted experts have helped organisations stay safe, compliant, and moving forward.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 22 | 15 contacts → | ||||
Strong evidence “Hartford Advisers is a specialist intelligence, research and due diligence firm.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 23 | 15 contacts → | ||||
Indirect evidence “Eurocom C.I.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 24 | 13 contacts → | ||||
Indirect evidence “HiveRisk is a boutique risk and compliance company founded by their CEO Kate Burt, an experienced solicitor with over 20 years experience in the legal sector.” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
| 25 | 12 contacts → | ||||
Indirect evidence “What’s it really like to be your customer-today, in every location, in every market?” Source: RevenueBase Database · checked Sep 19, 2026Thanks. The Data Team will review it. | |||||
RevenueBase Smart Search
RevenueBase Smart Search assesses information from a company’s LinkedIn profile, information supplied directly by the company, its website, and other publicly available sources. It uses that information to rate how closely the company relates to this list’s category: due diligence 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 due diligence firms.
- Partial evidence
- Its own public description names part of due diligence firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name due diligence 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 156 due diligence firms based in the United Kingdom
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Due diligence firms based in the United Kingdom at a glance
As of Sep 19, 2026Companies by employee count
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 156 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 due diligence 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 “due diligence 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 due diligence 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 due diligence 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, 797 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 19, 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.
Due diligence firms by metro
- Due diligence firms in London78
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 due diligence 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 due diligence firms are there based in the United Kingdom?
RevenueBase identified 156 due diligence 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?
Wilmington PLC, headquartered in Birmingham, tops this list with the largest team on record.
Which city has the most due diligence firms?
London leads with 78 headquartered companies, followed by Manchester (6) and Wokingham (3).
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 797 verified decision-maker contacts tracked across these 156 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 19, 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 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.