Company lists · Data refreshed September 2026

Top 25 Big 5 consulting firms based in the United Kingdom

Name: Big 5 consulting 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 23, 2026 3,656 companies tracked

RevenueBase identified 3,656 big 5 consulting firms headquartered in the United Kingdom as of September 2026 and tracks 51,692 professional contacts across them, including 21,429 with verified work emails and 5,034 with mobile numbers. London is the largest hub.

This list covers big 5 consulting 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 23, 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 23, 2026 86% judged on-target in blind review

3,656Companies

51,692Contacts tracked

21,429Verified emails

5,034Mobile numbers

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The 25 largest big 5 consulting firms based in the United Kingdom

Ranked by team size

Top 25 of 3,656 big 5 consulting firms based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 23, 2026. RevenueBase Smart Search rates how each company's information relates to big 5 consulting 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	Ey-Parthenon	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	10001+	17,070 contacts →
	Indirect evidence “Our unique combination of transformative strategy, transactions and corporate finance delivers real-world value – solutions that work in practice, not just on paper.” Source: RevenueBase Database · checked Sep 23, 2026
2	Baringa	Partial evidence	London, United KingdomHQ checked Sep 23, 2026	1,001-5,000	2,179 contacts →
	Partial evidence “Baringa is a global consulting firm that helps leaders drive meaningful change and create value.” Source: RevenueBase Database · checked Sep 23, 2026
3	Oc&c Strategy Consultants	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	501-1,000	1,011 contacts →
	Indirect evidence “At OC & C Strategy Consultants we have more than 35 years of experience at unpicking the most complex business challenges with simple, uncommon sense™.” Source: RevenueBase Database · checked Sep 23, 2026
4	Softwire	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	201-500	360 contacts →
	Indirect evidence “Softwire exists to help organisations use technology to deliver meaningful outcomes and a positive impact for themselves, their users and the world.” Source: RevenueBase Database · checked Sep 23, 2026
5	Emergn	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	501-1,000	351 contacts →
	Indirect evidence “Emergn is a global technology and management consultancy built on a simple conviction: the only sustainable competitive advantage is the way you work.” Source: RevenueBase Database · checked Sep 23, 2026
6	Davies	Partial evidence	London, United KingdomHQ checked Sep 23, 2026	5,001-10,000	329 contacts →
	Partial evidence “We are the global consulting division of Davies, accelerating business, technology and people performance across financial services including Retail Finance & Corporate Banking…” Source: RevenueBase Database · checked Sep 23, 2026
7	Cartesian	Partial evidence	London, United KingdomHQ checked Sep 23, 2026	201-500	302 contacts →
	Partial evidence “Cartesian is a specialist consulting firm focused on the global telecommunications, media, and technology industries and is now part of Bounteous, an AI services firm helping…” Source: RevenueBase Database · checked Sep 23, 2026
8	Gate ONE	Indirect evidence	King's Cross, United KingdomHQ checked Sep 23, 2026	201-500	281 contacts →
	Indirect evidence “Most organisations commit to bold growth ambitions but aren’t set up to deliver them.” Source: RevenueBase Database · checked Sep 23, 2026
9	Elixirr	Partial evidence	London, United KingdomHQ checked Sep 23, 2026	501-1,000	275 contacts →
	Partial evidence “An award-winning global consulting firm working with clients across a diverse range of markets, industries and geographies.” Source: RevenueBase Database · checked Sep 23, 2026
10	Transform	Strong evidence	London, United KingdomHQ checked Sep 23, 2026	201-500	255 contacts →
	Strong evidence “Transform is a fresh alternative to Big Consulting.” Source: RevenueBase Database · checked Sep 23, 2026
11	Moorhouse B Corp Certified	Partial evidence	London, United KingdomHQ checked Sep 23, 2026	201-500	247 contacts →
	Partial evidence “We’re a dynamic consulting firm, focused on delivering change.” Source: RevenueBase Database · checked Sep 23, 2026
12	Percipere	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	201-500	245 contacts →
	Indirect evidence “Percipere is a niche global consultancy, partnering companies in their evolution towards greater operational efficiency and profitability.” Source: RevenueBase Database · checked Sep 23, 2026
13	Albany Beck	Partial evidence	London, United KingdomHQ checked Sep 23, 2026	201-500	240 contacts →
	Partial evidence “Albany Beck is a client-first consulting firm helping financial services organisations deliver complex change and build capability, not dependency.” Source: RevenueBase Database · checked Sep 23, 2026
14	Actica Consulting	Partial evidence	Guildford, United KingdomHQ checked Sep 23, 2026	201-500	224 contacts →
	Partial evidence “Actica Consulting is a business and technology consultancy specialising in the delivery of complex transformation.” Source: RevenueBase Database · checked Sep 23, 2026
15	Clarify	Indirect evidence	Theale, United KingdomHQ checked Sep 23, 2026	51-200	191 contacts →
	Indirect evidence “Clarify helps global Technology companies achieve sustained and significant commercial success.” Source: RevenueBase Database · checked Sep 23, 2026
16	Azurian	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	201-500	178 contacts →
	Indirect evidence “The future has never moved this fast.” Source: RevenueBase Database · checked Sep 23, 2026
17	Clarasys	Partial evidence	London, United KingdomHQ checked Sep 23, 2026	51-200	170 contacts →
	Partial evidence “We are an employee-owned, award-winning international consulting firm that believes there’s a better way to do consultancy.” Source: RevenueBase Database · checked Sep 23, 2026
18	TXM Consult	Indirect evidence	Milton Keynes, United KingdomHQ checked Sep 23, 2026	51-200	166 contacts →
	Indirect evidence “In an uncertain, complex, and ambiguous world, business change is essential and inevitable.” Source: RevenueBase Database · checked Sep 23, 2026
19	Interex Group	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	51-200	160 contacts →
	Indirect evidence “InterEx Group is becoming the strategic partner of choice for organizations undergoing digital, business, and technology transformation.” Source: RevenueBase Database · checked Sep 23, 2026
20	The Berkeley Partnership	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	51-200	152 contacts →
	Indirect evidence “Founded in 1990, The Berkeley Partnership is an independent management consultancy, specialising in business transformation.” Source: RevenueBase Database · checked Sep 23, 2026
21	Sysdoc	Indirect evidence	London (uk), United KingdomHQ checked Sep 23, 2026	51-200	142 contacts →
	Indirect evidence “At Sysdoc we exist to help our clients to transform, adapt and operate in order for them to achieve their ambitions, and to provide our own people with opportunities that allow…” Source: RevenueBase Database · checked Sep 23, 2026
22	ORG	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	1,001-5,000	139 contacts →
	Indirect evidence “We believe that change is an opportunity to thrive.” Source: RevenueBase Database · checked Sep 23, 2026
23	Veran Performance	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	51-200	134 contacts →
	Indirect evidence “Winners of the UKOUG Business Transformation Advisory Partner of the Year Award 2025 Veran Performance is an advisory consultancy specialising in HR, Payroll, Procurement and…” Source: RevenueBase Database · checked Sep 23, 2026
24	Praesto Consulting	Indirect evidence	Staines-upon-thames, United KingdomHQ checked Sep 23, 2026	201-500	125 contacts →
	Indirect evidence “Technology consultancy providing expertise to complex IT programs.” Source: RevenueBase Database · checked Sep 23, 2026
25	Liqueo	Indirect evidence	London, United KingdomHQ checked Sep 23, 2026	51-200	123 contacts →
	Indirect evidence “Specialists in change and transformation across asset, wealth and insurance.” Source: RevenueBase Database · checked Sep 23, 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: big 5 consulting 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 big 5 consulting firms.
Partial evidence: Its own public description names part of big 5 consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name big 5 consulting 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 3,656 big 5 consulting firms based in the United Kingdom

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Big 5 consulting firms based in the United Kingdom at a glance

As of Sep 23, 2026

41.5%Verified-email coverage

9.7%Mobile-number coverage

14.1Average contacts per company

1-10Median size (employees)

38.4%Largest-city concentration · London

Sep 23, 2026Page data refreshed

Companies by employee count

1-10

2,835

11-50

532

51-200

182

201-500

501-1,000

1,001-5,000

5,001-10,000

10001+

Freshness & accuracy

How recently the business emails were verified and the company information checked

Email last verified

Median 26.0d

15,8970–30

5,01531–60

33461–90

4190–180

142180+

Company record updated

Median 74.0d

00–30

12,21331–60

24,87961–90

11,89290–180

2,708180+

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 big 5 consulting 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 “big 5 consulting 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 big 5 consulting 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 big 5 consulting 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, 21,429 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 23, 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.

Big 5 consulting firms by metro

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 big 5 consulting 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 big 5 consulting firms are there based in the United Kingdom?

RevenueBase identified 3,656 big 5 consulting 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?

Ey-Parthenon, headquartered in London, tops this list with the largest team on record.

Which city has the most big 5 consulting firms?

London leads with 1403 headquartered companies, followed by Manchester (68) and Bristol (45).

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 21,429 verified decision-maker contacts tracked across these 3,656 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 23, 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.