Company lists · Data refreshed September 2026

Top 25 Impact measurement consulting firms based in London, United Kingdom

Name: Impact measurement consulting firms based in London, United Kingdom
Creator: RevenueBase
License: https://creativecommons.org/licenses/by/4.0/

Compiled by the RevenueBase Data Team Data refreshed Sep 12, 2026 373 companies tracked

RevenueBase identified 373 impact measurement consulting firms headquartered in London, United Kingdom as of September 2026 and tracks 5,993 professional contacts across them, including 3,439 with verified work emails and 562 with mobile numbers. Across the United Kingdom, London is the largest hub for this category.

This list covers impact measurement consulting firms headquartered in London, 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 12, 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 12, 2026 86% judged on-target in blind review

373Companies

5,993Contacts tracked

3,439Verified emails

562Mobile numbers

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The 25 largest impact measurement consulting firms based in London, United Kingdom

Ranked by team size

Top 25 of 373 impact measurement consulting firms based in London, United Kingdom, ranked by team size, largest first. Data refreshed Sep 12, 2026. RevenueBase Smart Search rates how each company's information relates to impact measurement 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	SLR Consulting	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	1,001-5,000	3,848 contacts →
	Indirect evidence “SLR is a committed partner in our clients’ sustainability journeys.” Source: RevenueBase Database · checked Sep 12, 2026
2	The Smarty Train	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	86 contacts →
	Partial evidence “From employability and strategy formulation through to training programme design and delivery, we have been the engine behind award-winning and high-impact workplace initiatives…” Source: RevenueBase Database · checked Sep 12, 2026
3	Thirdway Partners	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	51-200	68 contacts →
	Partial evidence “ThirdWay Partners operates as an impact investment and advisory firm focused on creating inclusive sustainable development and impact.” Source: RevenueBase Database · checked Sep 12, 2026
4	Action Sustainability	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	51-200	62 contacts →
	Indirect evidence “Recognised for its commitment to employees with a sought-after Best Companies “One To Watch” industry standard, Action Sustainability offers a 3-in-1 solution through…” Source: RevenueBase Database · checked Sep 12, 2026
5	Eastside People	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	51-200	58 contacts →
	Partial evidence “Eastside People is a community of experienced professionals focused on helping charity, not-for-profit and social enterprise leaders to build the capacity and impact of their…” Source: RevenueBase Database · checked Sep 12, 2026
6	BRINK	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	54 contacts →
	Partial evidence “Brink is a behavioral science and innovation consultancy focused on social impact and international development across Africa and globally.” Source: RevenueBase Database · checked Sep 12, 2026
7	Bridges Outcomes Partnerships	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	48 contacts →
	Indirect evidence “Bridges Outcomes Partnerships is a not-for-profit social enterprise.” Source: RevenueBase Database · checked Sep 12, 2026
8	TH NK	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	n/a	41 contacts →
	Indirect evidence “You can now find us over at EPAM Continuum.” Source: RevenueBase Database · checked Sep 12, 2026
9	Brodie	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	39 contacts →
	Partial evidence “We are here to drive three significant changes: CHANGE CORPORATE IMPACT: help business to reframe and re-orient its role in society CHANGE CONSUMPTION: help brands re-wire for the…” Source: RevenueBase Database · checked Sep 12, 2026
10	The Good Economy Partnership Limited	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	31 contacts →
	Indirect evidence “From consultancy to collaborative field-building, The Good Economy (TGE) is a recognised thought leader and the ‘go to’ firm for organisations looking to deliver and report on…” Source: RevenueBase Database · checked Sep 12, 2026
11	Kaleidoscope Health And Care	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	28 contacts →
	Indirect evidence “Kaleidoscope is an award-winning social enterprise consultancy.” Source: RevenueBase Database · checked Sep 12, 2026
12	Chronos Sustainability	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	27 contacts →
	Indirect evidence “Chronos Sustainability is a specialist advisory company with the fundamental objective of delivering transformative, systemic change in the social and environmental performance of…” Source: RevenueBase Database · checked Sep 12, 2026
13	Scriptoria Sustainable Development Solutions	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	27 contacts →
	Indirect evidence “Scriptoria is an award-winning sustainable development consultancy delivering effective solutions for international development and research programmes through four core teams…” Source: RevenueBase Database · checked Sep 12, 2026
14	The Social Investment Consultancy Tsic	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	27 contacts →
	Indirect evidence “The Social Investment Consultancy (TSIC) is a global organisation with a network of experts committed to creating social change.” Source: RevenueBase Database · checked Sep 12, 2026
15	Mh&a	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	27 contacts →
	Indirect evidence “MH & A was founded in 2018 by Professor Matt Hamnett, who has worked at senior levels in central Government, corporate and social sector organisations.” Source: RevenueBase Database · checked Sep 12, 2026
16	Positive Luxury	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	25 contacts →
	Indirect evidence “Positive Luxury are the sustainability experts and growth partners for the luxury industry, working with global brands to turn sustainability into a competitive advantage.” Source: RevenueBase Database · checked Sep 12, 2026
17	MIME	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	23 contacts →
	Indirect evidence “Mime is expert at turning data into useful and engaging insights.” Source: RevenueBase Database · checked Sep 12, 2026
18	Trust Impact	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	22 contacts →
	Partial evidence “It’s never been more important for organisations to explore, align, amplify and communicate the positive impact you’re having.” Source: RevenueBase Database · checked Sep 12, 2026
19	Good Innovation	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	22 contacts →
	Indirect evidence “We help charities transform their income and services.” Source: RevenueBase Database · checked Sep 12, 2026
20	KOREO	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	1-10	18 contacts →
	Indirect evidence “We’re a purpose-driven consultancy that transforms how people lead, learn, collaborate and operate- strengthening their capacity to build a more just and regenerative world.” Source: RevenueBase Database · checked Sep 12, 2026
21	Firetail	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	16 contacts →
	Indirect evidence “Firetail is a strategy consultancy working to achieve social progress.” Source: RevenueBase Database · checked Sep 12, 2026
22	Impact & Influence	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	1-10	15 contacts →
	Partial evidence “I&I is a leading international impact-driven strategic consultancy.” Source: RevenueBase Database · checked Sep 12, 2026
23	The Social Innovation Partnership Tsip	Partial evidence	London, United KingdomHQ checked Sep 12, 2026	11-50	15 contacts →
	Partial evidence “The Social Innovation Partnership (TSIP) is a trusted advisor to public, private and social sector organisations seeking to maximise their social impact.” Source: RevenueBase Database · checked Sep 12, 2026
24	International Fundraising Consultancy	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	1-10	15 contacts →
	Indirect evidence “IFCo is an award-winning consultancy specialising in fundraising, management, marketing and communications.” Source: RevenueBase Database · checked Sep 12, 2026
25	Edenlab	Indirect evidence	London, United KingdomHQ checked Sep 12, 2026	1-10	15 contacts →
	Indirect evidence “Welcome to EdenLab \| We help our clients turn sustainability into real commercial advantage.” Source: RevenueBase Database · checked Sep 12, 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: impact measurement 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 impact measurement consulting firms.
Partial evidence: Its own public description names part of impact measurement consulting firms, so it works in or next to the category without describing itself that way.
Indirect evidence: The description shown does not name impact measurement 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 373 impact measurement consulting firms based in London, United Kingdom

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Impact measurement consulting firms based in London, United Kingdom at a glance

As of Sep 12, 2026

57.4%Verified-email coverage

9.4%Mobile-number coverage

16.1Average contacts per company

1-10Median size (employees)

Sep 12, 2026Page data refreshed

Companies by employee count

1-10

283

11-50

51-200

1,001-5,000

10001+

Freshness & accuracy

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

Email last verified

Median 14.0d

2,9390–30

47731–60

1661–90

190–180

6180+

Company record updated

Median 62.0d

00–30

2,89931–60

2,28361–90

47690–180

335180+

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 impact measurement 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 London, United Kingdom whose own description of what they do matches “impact measurement 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 impact measurement 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 impact measurement consulting firms, and records with no verified work email. Companies headquartered outside London 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, 3,439 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 12, 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.

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 impact measurement 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 impact measurement consulting firms are there based in London, United Kingdom?

RevenueBase identified 373 impact measurement consulting firms headquartered in London, 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?

SLR Consulting, headquartered in London, tops this list with the largest team on record.

Which city in the United Kingdom has the most impact measurement consulting firms?

London leads the United Kingdom with 305 headquartered companies, followed by Bristol (15) and Manchester (14).

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 3,439 verified decision-maker contacts tracked across these 373 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 12, 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.