Company lists · Data refreshed September 2026

Top 25 Merger integration consulting firms based in the United Kingdom

RevenueBase identified 1,300 merger integration consulting firms headquartered in the United Kingdom as of September 2026 and tracks 16,149 professional contacts across them, including 5,598 with verified work emails. London is the largest hub.

This list covers merger integration 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 28, 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 28, 2026 86% judged on-target in blind review
1,300Companies
16,149Contacts tracked
5,598Verified emails
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The 25 largest merger integration consulting firms based in the United Kingdom

Ranked by team size
Top 25 of 1,300 merger integration consulting firms based in the United Kingdom, ranked by team size, largest first. Data refreshed Sep 28, 2026. RevenueBase Smart Search rates how each company's information relates to merger integration 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.
#CompanyRevenueBase Smart SearchHeadquartersEmployeesContacts
1Indirect evidencePortlethen, United KingdomHQ checked Sep 28, 202610001+4,109 contacts →

Indirect evidence

Source: RevenueBase Database · checked Sep 28, 2026
2Partial evidenceLondon, United KingdomHQ checked Sep 28, 20261,001-5,0002,179 contacts →

Partial evidence

“Baringa is a global consulting firm that helps leaders drive meaningful change and create value.”

Source: RevenueBase Database · checked Sep 28, 2026
3Indirect evidenceLondon, United KingdomHQ checked Sep 28, 2026n/a1,361 contacts →

Indirect evidence

“As of April 1, 2019, JLT Group is now part of Marsh & McLennan Companies (MMC).”

Source: RevenueBase Database · checked Sep 28, 2026
4Indirect evidenceLondon, United KingdomHQ checked Sep 28, 2026501-1,0001,011 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 28, 2026
5Indirect evidenceEdinburgh, United KingdomHQ checked Sep 28, 2026201-500414 contacts →

Indirect evidence

“Morton Fraser MacRoberts (MFMac) is a leading independent Scottish law firm, known for combining deep legal expertise with clear, practical advice that helps clients achieve their…”

Source: RevenueBase Database · checked Sep 28, 2026
6Indirect evidenceLondon, United KingdomHQ checked Sep 28, 20261,001-5,000362 contacts →

Indirect evidence

“Berwin Leighton Paisner and Bryan Cave have combined to form Bryan Cave Leighton Paisner LLP.”

Source: RevenueBase Database · checked Sep 28, 2026
7Partial evidenceLondon, United KingdomHQ checked Sep 28, 2026501-1,000275 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 28, 2026
8Partial evidenceLondon, United KingdomHQ checked Sep 28, 2026201-500247 contacts →

Partial evidence

“We’re a dynamic consulting firm, focused on delivering change.”

Source: RevenueBase Database · checked Sep 28, 2026
9Partial evidenceLondon, United KingdomHQ checked Sep 28, 2026201-500240 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 28, 2026
10Indirect evidenceLondon, United KingdomHQ checked Sep 28, 2026201-500206 contacts →

Indirect evidence

“Welcome to the Protiviti perspective.”

Source: RevenueBase Database · checked Sep 28, 2026
11Partial evidenceLondon, United KingdomHQ checked Sep 28, 2026n/a165 contacts →

Partial evidence

“Strategic development for already dynamic businesses, successful mergers & acquisitions between household names, technology planning in cutting edge industries and real-world…”

Source: RevenueBase Database · checked Sep 28, 2026
12Indirect evidenceLondon (uk), United KingdomHQ checked Sep 28, 202651-200142 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 28, 2026
13Indirect evidenceLondon, United KingdomHQ checked Sep 28, 20261,001-5,000139 contacts →

Indirect evidence

“We believe that change is an opportunity to thrive.”

Source: RevenueBase Database · checked Sep 28, 2026
14Indirect evidenceLondon, United KingdomHQ checked Sep 28, 202651-200123 contacts →

Indirect evidence

“Specialists in change and transformation across asset, wealth and insurance.”

Source: RevenueBase Database · checked Sep 28, 2026
15Indirect evidenceLondon, United KingdomHQ checked Sep 28, 202611-50122 contacts →

Indirect evidence

“Athens helps clients make superior investment decisions and supports them to deliver value from these decisions through timely implementation.”

Source: RevenueBase Database · checked Sep 28, 2026
16Indirect evidenceLondon, United KingdomHQ checked Sep 28, 202651-200115 contacts →

Indirect evidence

“Oaklin is an independent management consultancy.”

Source: RevenueBase Database · checked Sep 28, 2026
17Partial evidenceLondon, United KingdomHQ checked Sep 28, 202651-20096 contacts →

Partial evidence

“Oxygen + Synergy = OXYGY: a new breed of consulting company.”

Source: RevenueBase Database · checked Sep 28, 2026
18Partial evidenceLondon, United KingdomHQ checked Sep 28, 202651-20075 contacts →

Partial evidence

“We redefined management consulting to make it better for clients and better for consultants.”

Source: RevenueBase Database · checked Sep 28, 2026
19Indirect evidenceLondon, United KingdomHQ checked Sep 28, 202651-20074 contacts →

Indirect evidence

“Whether complex transformation is required across your business or you are seeking support with a small project, we are here to help.”

Source: RevenueBase Database · checked Sep 28, 2026
20Indirect evidenceBath, United KingdomHQ checked Sep 28, 202611-5071 contacts →

Indirect evidence

“Nine Feet Tall specialise in managing and delivering complex change programmes, combining the power of people and technology.”

Source: RevenueBase Database · checked Sep 28, 2026
21Partial evidenceLondon, United KingdomHQ checked Sep 28, 202651-20060 contacts →

Partial evidence

“As of 24th March 2025, Farsight Consulting will operate under Version 1.”

Source: RevenueBase Database · checked Sep 28, 2026
22Indirect evidenceLondon, United KingdomHQ checked Sep 28, 202651-20059 contacts →

Indirect evidence

“We’re people-first and culture-obsessed.”

Source: RevenueBase Database · checked Sep 28, 2026
23Indirect evidenceManchester, United KingdomHQ checked Sep 28, 202651-20055 contacts →

Indirect evidence

“An award-winning specialist delivering high-impact, senior-led services across the deal lifecycle.”

Source: RevenueBase Database · checked Sep 28, 2026
24Partial evidenceLondon, United KingdomHQ checked Sep 28, 202651-20053 contacts →

Partial evidence

“We’re a technology and transformation consulting partner that helps organisations accelerate change with confidence.”

Source: RevenueBase Database · checked Sep 28, 2026
25Indirect evidenceManchester, United KingdomHQ checked Sep 28, 202651-20050 contacts →

Indirect evidence

“Collinson Grant helps clients throughout the world to improve efficiency and profitability.”

Source: RevenueBase Database · checked Sep 28, 2026

Showing 25 of 1,300 merger integration consulting firms based in the United Kingdom

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Merger integration consulting firms based in the United Kingdom at a glance

As of Sep 28, 2026
34.7%Verified-email coverage
12.4Average contacts per company
1-10Median size (employees)
45.5%Largest-city concentration · London
Sep 28, 2026Page data refreshed

Companies by employee count

1-10
987
11-50
218
51-200
65
201-500
10
501-1,000
4
1,001-5,000
6
10001+
2

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 1,300 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 merger integration 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 “merger integration 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 merger integration 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 merger integration 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, 5,598 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 28, 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.

Merger integration 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 merger integration 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 merger integration consulting firms are there based in the United Kingdom?

RevenueBase identified 1,300 merger integration 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?

KCA Deutag, headquartered in Portlethen, tops this list with the largest team on record.

Which city has the most merger integration consulting firms?

London leads with 592 headquartered companies, followed by Manchester (22) and Glasgow (20).

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 5,598 verified decision-maker contacts tracked across these 1,300 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 28, 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.