2023 was a rough year in tech, and the UK was no exception.
Startups raised around half the figure of 2021’s record-breaking, $38.7bn year — pulling in $18.4bn.
While fundraising troubles have continued into 2024 (figures are currently on track to hit similar levels to last year) there are still several startups scaling at pace.
Like 2023, climate tech dominates this year’s 10 fastest-growing startups, counting four companies among the ranks, following another record year on the fundraising roadshow for the sector. There’s also a fintech, biotech, edtech, foodtech, agritech and a GenAI startup on the list.
Sifted used data from Dealroom to put together the fastest-growing UK startup teams by headcount over the last 12 months. To avoid results being skewed by early-stage businesses making lots of hires while growing quickly, companies must have raised at least $50m and have at least 25 employees to be considered.
1/ Weev
HQ city: Belfast, Northern Ireland
Founded: 2022
Headcount growth over the last 12 months: 167% to 48 employees
Weev operates an EV charging network across Northern Ireland. It raised a £50m round from Octopus Investments in May 2023 — the country’s largest ever VC round, according to Dealroom data.
2/ Vertice
HQ city: London
Founded: 2021
Headcount growth over the last 12 months: 160% to 257 employees
London-based Vertice is a spend management platform that finance teams can use to gain visibility on their software and cloud spend.
It’s raised $52.2m from investors including Bessemer Venture Partners and 83North — including a €23m Series B in January this year.
3/ THIS
HQ city: London
Founded: 2017
Headcount growth over the last 12 months: 141% to 222 employees
Plant-based ‘meat’ maker THIS aims to have its first profitable quarter by the end of 2024, after appointing a new CEO and streamlining operations.
It’s the fourth largest brand in the UK’s plant-based category — and has picked up $53.9m in funding, from investors including Seedcamp, Backed VC and ITV.
4/ Complement Therapeutics
HQ city: London
Founded: 2020
Headcount growth over the last 12 months: 100% to 28 employees
Complement Therapeutics is developing treatments for diseases in the area of ophthalmology.
It’s raised $84.7m from investors, including a €72m Series A in April 2023.
5/ GeoPura
HQ city: Newcastle
Founded: 2019
Headcount growth over the last 12 months: 95% to 82 employees
GeoPura uses renewable energy — like solar or wind — to create hydrogen-based zero-emission fuels, which it then converts to electricity.
It’s raised a total of $122m, most recently a £56m round in February this year, from investors including Barclays and UK Infrastructure Bank.
6/ Newcleo
HQ city: London
Founded: 2021
Headcount growth over the last 12 months: 91% to 434 employees
Newcleo is developing lead-cooled small modular reactors (SMRs) fuelled with radioactive waste — one of six types of “fourth-generation” reactors (also known as advanced reactors) which will begin to be rolled out in the 2030s.
It’s Europe’s only nuclear unicorn — valued between $1.3bn-$2bn, according to Dealroom estimates — and the best-funded nuclear startup in Europe by some margin. It’s raised a total of €487m in funding, including an €87m first close of a targetted €1bn round in May.
7/ GrowUp Farms
HQ city: London
Founded: 2013
Headcount growth over the last 12 months: 88% to 79 employees
Vertical farming startup GrowUp has raised $134m since launching over a decade ago. Its most recent round came in February 2022, when it picked up £100m from Generate Capital.
8/ Field
HQ city: London
Founded: 2020
Headcount growth over the last 12 months: 75% to 86 employees
The renewable energy infrastructure startup makes it onto Sifted’s fastest growing list for the second year running — after reaching number five in the 2023 edition.
Founded by now-collapsed energy supplier Bulb cofounder Amit Gudka, Field works with landowners and communities to build battery-based energy storage sites that supply the grid.
The LocalGlobe and Plural-backed startup raised £200m in July 2023 to expand its battery projects in the UK and to move into Europe. The round took Field’s total funding to £240m.
9/ Zen Educate
HQ city: London
Founded: 2017
Headcount growth over the last 12 months: 71% to 814 employees
Zen Educate is an online platform that connects supply teachers to jobs in schools. It’s raised $84.7m, including a $37m Series B in May this year.
10/ Synthesia
HQ city: London
Founded: 2017
Headcount growth over the last 12 months: 71% to 361 employees
Generative AI unicorn Synthesia was one of the few European startups to hit the $1bn milestone in 2023, which came after it raised $90m in June that year.
Synthesia uses GenAI to generate professional-looking AI videos from text and is one of the old guards of the GenAI space. The company has more than 50k customers, with nearly half of Fortune 500 companies using its tech to automatically generate videos with virtual avatars. The NHS, for example, has used it to make explanatory videos in different languages.
Editor's note: This article has been updated from a previous version that included Field as the fastest-growing company. It has since been confirmed that Field's headcount in May 2023 was 49 and has increased to 86 in the last 12 months at a growth rate of 75%.
