May 29, 2023

The 10 fastest-growing startups in the UK

We crunched the numbers to find the tech companies in the UK who have hired the most over the past 12 months

Across a chaotic 2022, scores of UK tech companies laid off staff as they scrambled to balance the books — the challenges have continued into 2023, with funding into UK startups on a downward trajectory after Q1.

But a number of UK startups are weathering the storm and still have their sights set on scaling. Sifted has tracked down the 10 fastest-growing tech companies in the UK over the past 12 months.

Climate tech companies — one of the few sectors in European tech to raise more in 2022 than 2021 — dominate the list. Two fintechs also made the cut alongside a healthtech. 


Using data from Dealroom, Sifted measured headcount growth rate over the past year. All the companies featured were founded after 2005 and, to avoid the results being skewed by small businesses making lots of hires, startups needed to have raised $50m or more to be considered.

1/ Tranch

Tranch provides buy now, pay later financing to businesses to pay for SaaS and services. The fintech is part of a wave of B2B buy now, pay later startups that have begun to pick up serious funding from VCs over the past couple of years. 

It raised a $100m seed round in January 2023 — split 50/50 in debt and equity — as it looked to double down on the US market.

Founded: 2021
HQ: London
Team growth last 12 months: 300% to 16 employees
Total funding: $52.3m

2/ Newcleo

Newcleo is part of a new generation of nuclear energy startups looking to make the sector more sustainable with small modular reactors (SMRs). SMRs are much smaller than traditional reactors so are cheaper to build and produce less nuclear waste.

It raised €300m in June 2022 and has grown its headcount 141% in the past 12 months.

Founded: 2021
HQ: London
Team growth last 12 months: 182% to 1,181 employees
Total funding: $448m

3/ Raw Charging

Electric vehicle (EVs) charging infrastructure company Raw Charging raised one of the largest rounds of 2022 in the UK, when it picked up $330m in July. 

The company supplies businesses with charging points for EVs and more than doubled its headcount over the past year. 

Founded: 2018
HQ: Leeds
Team growth last 12 months: 141% to 41 employees
Total funding: $330m

4/ Octopus Energy

The energy provider managed to survive the energy crisis in 2021-22 which saw 29 other energy suppliers in the UK fail — including former VC darling Bulb, which it acquired in 2022. It made a £141m loss in 2022, but expects to hit profitability this year. 

In May, founder and CEO Greg Jackson said the company was trialling generative AI in its customer service. It last raised in a $225m round in July 2022.

Founded: 2015
HQ: London
Team growth last 12 months: 139% to 2421 employees
Total funding: $1.7bn

5/ Field

Founded by now-collapsed energy supplier Bulb cofounder Amit Gudka, the renewable energy infrastructure startup works with landowners and communities to build battery-based energy storage sites that supply the grid. 

It raised £30m in equity from Taavet Hinrikus’s €250m VC fund Plural in June 2022.  

Founded: 2020
HQ: London
Team growth last 12 months: 129% to 55 employees
Total funding: $52.8m

6/ Freedom Fibre

The fibre optic broadband infrastructure company has more than doubled its headcount since raising £84m in equity and £16m in debt in May 2022. 


Founded: 2020
HQ: Manchester
Team growth last 12 months: 125% to 162 employees
Total funding: $111m

7/ Kroo

The mobile-only neobank raised £26m in May last year and a month later was granted a full banking licence, meaning it can offer personal current accounts to customers. 

It's just the second company to be granted that power since 2016 — and larger fintechs like Revolut and Wise are still on the hunt for their banking licences. 

Founded: 2016
HQ: London
Team growth last 12 months: 123% to 172 employees
Total funding: $69m

8/ Zoe Health

Gut microbiome and nutrition startup Zoe raised a $30m Series B extension in December 2022. The startup told Sifted in an interview in February its key focus is scaling, as it looks to meet demand for its at-home microbiome testing kits and supply the hundreds of thousands of customers on its waiting list. 

It more than doubled its headcount in the past year, and picked up a $2.5m micro-Series B extension from Steven Bartlett’s Flight Fund in March.

Founded: 2017
HQ: London
Team growth last 12 months: 121% to 323 employees
Total funding: $84.5m

9/ Venterra

Venterra provides operational and project management support to wind farms, and raised a £40m round in February 2022. 

Founded: 2021
HQ: Sheffield
Team growth last 12 months: 113% to 32 employees
Total funding: $52.8m

10/ Zenobe Energy

The EV infrastructure startup operates battery storage facilities and charging points across the UK. It last raised in a £235m debt round in February 2023.

Founded: 2017
HQ: London
Team growth last 12 months: 108% to 191 employees
Total funding: $297m

Kai Nicol-Schwarz

Kai Nicol-Schwarz is a reporter at Sifted. He covers UK tech and healthtech, and can be found on X and LinkedIn