Company lists · Data refreshed September 2026
Top 25 Venture capital cleantech firms based in London, United Kingdom
RevenueBase identified 81 venture capital cleantech firms headquartered in London, United Kingdom as of September 2026 and tracks 765 professional contacts across them, including 409 with verified work emails. Across the United Kingdom, London is the largest hub for this category.
This list covers venture capital cleantech 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 29, 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 venture capital cleantech firms based in London, United Kingdom
Ranked by team size| # | Company | Contacts | |||
|---|---|---|---|---|---|
| 1 | 153 contacts → | ||||
Indirect evidence “At Octopus Energy Generation, we’re building green power for the future, from large-scale solar to onshore and offshore wind, and innovative initiatives like the Fan Club.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 2 | 62 contacts → | ||||
Partial evidence “Climate Investment is a US and UK-based independently managed specialist investor focused on accelerating capital-efficient decarbonization of heavy emitting sectors.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 3 | 43 contacts → | ||||
Indirect evidence “The reference early stage investor for UK climate innovation.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 4 | 41 contacts → | ||||
Indirect evidence “Founded in 2018 by ambitious entrepreneurs, National Energy is a US-backed, privately funded group active globally across the renewable energy sector.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 5 | 31 contacts → | ||||
Strong evidence “AP Ventures is an independent venture capital firm headquartered in London, with offices in San Francisco and South Africa.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 6 | 29 contacts → | ||||
Strong evidence “Founded in 2005, ETF Partners (The Environmental Technologies Fund) stands as Europe's original venture capital firm dedicated to sustainability and impact investing.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 7 | 29 contacts → | ||||
Indirect evidence “With European roots and decades of experience, we invest globally in exceptional startups and talented teams.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 8 | 24 contacts → | ||||
Indirect evidence “At CLT, we believe clean technology is essential to building a resilient, competitive, and sustainable economy.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 9 | 24 contacts → | ||||
Strong evidence “C5 Capital is a specialist Venture Capital Firm focused on cybersecurity, space and energy security.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 10 | 19 contacts → | ||||
Indirect evidence “Taranis is an investment and asset management company owned by the Perenco Group.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 11 | 14 contacts → | ||||
Indirect evidence “Clean Energy Transition LLP is an investment management partnership focused on fundamental equity investing.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 12 | 13 contacts → | ||||
Indirect evidence “CGF invest in tech innovations that reduce greenhouse gas emissions or improve resource efficiency across power, transport, industry, buildings, waste and water.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 13 | 11 contacts → | ||||
Indirect evidence “Buckthorn invests in industrial businesses providing products and services that support the growth and integration of renewable energy, lower emissions, energy efficiency and…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 14 | 11 contacts → | ||||
Indirect evidence “We invest in new energy technologies.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 15 | 11 contacts → | ||||
Indirect evidence “Telis Energy is a UK-based green energy projects developer and investor.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 16 | 9 contacts → | ||||
Partial evidence “Magnesium Capital is a growth-oriented private equity firm based in London that focuses on investing in fast-growing technology and tech-led businesses that are transforming the…” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 17 | 9 contacts → | ||||
Strong evidence “Early-stage venture capital investor focused on technologies driving the Energy transition.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 18 | 9 contacts → | ||||
Indirect evidence “Investments and consulting services” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 19 | 8 contacts → | ||||
Indirect evidence “Blume Equity is a climate-tech growth equity firm with offices in London and Amsterdam focusing on companies driving sustainable outcomes for planet and people.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 20 | 8 contacts → | ||||
Strong evidence “Impact-driven venture and growth capital fund centred on Energy Decarbonization, Hydrogen, Water risks/Food Security and AI driven solutions.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 21 | 7 contacts → | ||||
Indirect evidence “Susgen is a London-based private investment firm focused on fighting climate change.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 22 | 7 contacts → | ||||
Indirect evidence “EcoPragma is dedicated to the net zero transition.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 23 | 7 contacts → | ||||
Partial evidence “Ekta raises capital for companies addressing environmental and social challenges through technology and innovation.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 24 | 6 contacts → | ||||
Indirect evidence “Investing in technology companies that enable a more sustainable built environment.” Source: RevenueBase Database · checked Sep 29, 2026Thanks. The Data Team will review it. | |||||
| 25 | 5 contacts → | ||||
Strong evidence “CleanTech Capital Advisors (CCA) is a pioneering corporate finance advisory firm, providing transaction advisory services for companies in the CleanTech sector.” Source: RevenueBase Database · checked Sep 29, 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: venture capital cleantech 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 venture capital cleantech firms.
- Partial evidence
- Its own public description names part of venture capital cleantech firms, so it works in or next to the category without describing itself that way.
- Indirect evidence
- The description shown does not name venture capital cleantech 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 81 venture capital cleantech firms based in London, United Kingdom
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Venture capital cleantech firms based in London, United Kingdom at a glance
As of Sep 29, 2026Companies by employee count
Email recency for this list is measured across the whole United Kingdom list rather than for London, so it is reported there. Company counts and contact totals on this page are exact for London, over 81 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 venture capital cleantech 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 “venture capital cleantech 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 venture capital cleantech 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 venture capital cleantech 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, 409 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 29, 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 venture capital cleantech 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 venture capital cleantech firms are there based in London, United Kingdom?
RevenueBase identified 81 venture capital cleantech 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?
Octopus Energy Generation, headquartered in London, tops this list with the largest team on record.
Which city in the United Kingdom has the most venture capital cleantech firms?
London leads the United Kingdom with 81 headquartered companies, followed by Bristol (3) and Edinburgh (2).
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 409 verified decision-maker contacts tracked across these 81 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 29, 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.
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