Top Climate tech companies in London
Companies decarbonising power, transport, agriculture, and industry. Filtered to companies headquartered in London.
- IndustryClimate tech
- HQLondon
- Matches449
Built from a search like: “Top Climate tech companies in London”
Ranked by current headcount across Climate tech companies headquartered in London. Refreshed daily.
- 1SLR Consulting· London, England, United Kingdom
- Series C
- 4.1k employees
- Founded 1994
- 2Equans UK & Ireland· London, England, United Kingdom
- Grant
- 2.3k employees
- 3Safetykleen· Brentford, England, United Kingdom
- 1.4k employees
- Founded 1973
- 4CDP· London, England, United Kingdom
- Grant
- 1.2k employees
- Founded 2000
- 5Anthesis Group· London, England, United Kingdom
- Private equity
- 894 employees
- Founded 2013
- 6Trojan Technologies· London, Ontario, Canada
- 780 employees
- Founded 1947
- 7Temple· London, England, United Kingdom
- 503 employees
- Founded 1997
- 8Energy Saving Trust· London, England, United Kingdom
- Seed
- 470 employees
- Founded 2024
- 9The Carbon Trust· London, England, United Kingdom
- Series unknown
- 407 employees
- Founded 2001
- 10Lynker· Leesburg, Virginia, United States
- 389 employees
- Founded 2007
- 11Janus Global Operations LLC· Lenoir City, Tennessee, United States
- 376 employees
- Founded 1987
- 12Ambipar | Europe· London, England, United Kingdom
- 347 employees
- 13Systemiq Ltd.· London, England, United Kingdom
- Series unknown
- 333 employees
- Founded 2016
- 14Reconomy· London, England, United Kingdom
- 319 employees
- Founded 1994
- 15International Water Association· London, England, United Kingdom
- 288 employees
- Founded 1947
- 16Climate Group· London, England, United Kingdom
- 279 employees
- Founded 2004
- 17Reconomy Connect· London, England, United Kingdom
- 277 employees
- Founded 1994
- 18Etude· London, England, United Kingdom
- 264 employees
- Founded 2012
- 19INTEC Energy Solutions· London, England, United Kingdom
- 262 employees
- 20enfinium· London, England, United Kingdom
- Debt
- 260 employees
- Founded 2021
- 21Tersus (Marlowe Environmental Services)· Rainham, England, United Kingdom
- 258 employees
- Founded 1985
- 22Hydro Cleansing· Croydon, England, United Kingdom
- 258 employees
- Founded 2000
- 23JD Ross Energy· London, England, United Kingdom
- 222 employees
- Founded 2015
- 24Salix· London, England, United Kingdom
- Grant
- 220 employees
- Founded 2004
- 25Carbon Clean· London, England, United Kingdom
- Series C
- 197 employees
- Founded 2009
Find engineers at Climate tech companies in London
London has long been a hub for Climate tech, and the list above ranks the largest Climate tech companies headquartered there by current headcount, drawn from public LinkedIn and Crunchbase records. With 449 matching companies in our index, this is a good map of where the Climate tech talent in Londonlives — useful whether you’re recruiting, partnering, or sizing a market.
The biggest Climate tech companies in London tend to be the gravitational centres for specialised talent — senior engineers, ML researchers, applied scientists, designers — while the smaller ones compete on speed, equity, and proximity to founders.
Refolk converts this list into a live search. Ask for “Climate tech engineers in Londonhiring senior staff” or “founders of Climate tech companies in Londonwho left in the last 12 months” and Refolk returns a ranked shortlist with the evidence that earned each person a spot.
How this list is built
Last refreshed: Thu, 07 May 2026 08:52:24 GMT
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