Company lists · Data refreshed September 2026
Top 25 Iso audit companies based in the United Kingdom
RevenueBase identified 432 iso audit companies headquartered in the United Kingdom as of September 2026 and tracks 27,526 professional contacts across them, including 8,696 with verified work emails. London is the largest hub.
This list covers iso audit 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, 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.
The 25 largest iso audit companies based in the United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 23,155 contacts → | ||||
Indirect evidence “Intertek is a leading Total Quality Assurance provider to industries worldwide.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 2 | 776 contacts → | ||||
Indirect evidence “Testing, inspection, certification and compliance is our core business so that’s what gets 100% of our focus.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 3 | 291 contacts → | ||||
Indirect evidence “The Citation Group offer unrivalled compliance and quality services to over businesses across the UK, Australia, New Zealand, and Canada.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 4 | 267 contacts → | ||||
Indirect evidence “NQA is a leading global certification body, respected for providing flexible and supportive certification and training services that are technically advanced and meet the needs of…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 5 | 138 contacts → | ||||
Partial evidence “Amtivo Group provides expert certification services for ISO standards, as well as training and related services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 6 | 115 contacts → | ||||
Partial evidence “We believe in keeping ISO certification simple, so that's exactly what we do.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 7 | 100 contacts → | ||||
Indirect evidence “ERM CVS provides science-based, independent assurance, verification certification and training services for the world’s leading organizations.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 8 | 99 contacts → | ||||
Indirect evidence “Our reputation for providing outstanding service explains why clients who joined us when we first opened our doors in 1993 are still with us today.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 9 | 89 contacts → | ||||
Indirect evidence “Phenna Group is a global family of specialist businesses delivering Testing, Inspection, Certification and Compliance (TICC) services to customers worldwide.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 10 | 88 contacts → | ||||
Indirect evidence “Your partners in quality.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 11 | 72 contacts → | ||||
Indirect evidence “NSI is the UK’s most recognised certification body for fire and security.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 12 | 50 contacts → | ||||
Partial evidence “International Associates (IA) is a leading provider of assessment, audit, verification, certification and training services.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 13 | 47 contacts → | ||||
Indirect evidence “GCS Compliance Ltd are a specialist independent auditing company providing quality safety, expert technical, compliance management consultancy services and professional training…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 14 | 34 contacts → | ||||
Partial evidence “Centre for Assessment Ltd is a leading certification body, delivering audits and assessments to thousands of clients both nationally and internationally.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 15 | 28 contacts → | ||||
Partial evidence “Clear Quality is a professional ISO Consultancy business and Prime Training provider based in South Yorkshire.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 16 | 22 contacts → | ||||
Indirect evidence “Control Union (UK) is an independent, accredited certification and inspection body helping businesses confidently navigate sustainability.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 17 | 21 contacts → | ||||
Indirect evidence “CES is a renowned calibration and inspection company catering to the automotive, industrial, and aviation sectors with a network of skilled engineers throughout the nation.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 18 | 21 contacts → | ||||
Indirect evidence “The certification body of choice for the built environment.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 19 | 21 contacts → | ||||
Indirect evidence “TPT is a leading provider of training and consultancy, serving customers around the world.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 20 | 21 contacts → | ||||
Indirect evidence “ATC International is based in the United Kingdom and provides international conformity assessment and certification services across the world.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 21 | 20 contacts → | ||||
Indirect evidence “We are proudly the only employee-owned UKAS-accredited certification and verification body in the UK.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 22 | 19 contacts → | ||||
Partial evidence “Business Excellence & Management Consortium (BEMCON) is a professional training, consulting, and auditing organization specializing in ISO standards, occupational health & safety…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 23 | 18 contacts → | ||||
Partial evidence “CQS (Certified Quality Systems) Ltd delivers straightforward, practical ISO certification with over 25 years of experience.” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 24 | 18 contacts → | ||||
Indirect evidence “We provide a wide range of auditing, certification and gap analysis services on; AI, DORA, NIS2, Information Security, Business Continuity, International IT Service, GDPR and…” Source: RevenueBase Database · checked Sep 20, 2026Thanks. The Data Team will review it. | |||||
| 25 | 18 contacts → | ||||
Partial evidence “Premier Advisory Group is certified to ISO Standard 9001:2015 for the provision of management consultancy, our core objective has always been to drive and support continual…” Source: RevenueBase Database · checked Sep 20, 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: iso audit companies. 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 iso audit companies.
- Partial evidence
- Its own public description names part of iso audit companies, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name iso audit companies. 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 432 iso audit companies based in the United Kingdom
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Iso audit companies based in the United Kingdom at a glance
As of Sep 20, 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 432 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 iso audit companies, 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 “iso audit companies”. 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 iso audit companies), 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 iso audit 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 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, 8,696 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.
Iso audit companies by metro
- Iso audit companies in London68
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 iso audit companies, 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 iso audit companies are there based in the United Kingdom?
RevenueBase identified 432 iso audit 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?
Intertek, headquartered in London, tops this list with the largest team on record.
Which city has the most iso audit companies?
London leads with 68 headquartered companies, followed by Manchester (17) and Aberdeen (9).
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 8,696 verified decision-maker contacts tracked across these 432 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.
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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.