The UK is the third largest AI market in the world, behind only the United States and China and if the noise from the government is anything to go by, its AI sector will be one of its most important assets in the world.   

So, who are the biggest players in UK AI? Which companies are leading the way for what could be the most significant segment of the tech industry in the world?   

Determining what counts as an ‘AI company’ is in 2025 is a matter of interpretation as practically every tech firm in the world has some connection to artificial intelligence.  

This list is strictly looking at companies where the primary product and business is AI software, with an honourable mention to Arm, the Cambridge-based chip designer integral to the AI industry with a market cap of $165.7bn. 

Here are Britain’s 10 biggest AI companies. 

(Valuations are based on Dealroom data) 

ElevenLabs 

Valuation: $3.2bn 

Though it may top the list of the UK’s most valuable AI companies, ElevenLabs is also one of its youngest. Founded in 2022, the London and New York-based startup’s rise has been meteoric, going from a $2m (£1.58m) seed round in January 2023 to a $180m $500m Series C just two years later. 

ElevenLabs has built a text-to-speech system that eerily captures the realistic quirks of human speech. The company’s AI voice generation is available in over two dozen languages and has APIs available for others building AI voice tools. Backers include Andreessen Horowitz and Sequoia. 

Wayve 

Valuation: $3bn 

The UK’s biggest autonomous vehicle company, Wayve is at the forefront of what the British government expects to be a major technology of the future. Wayve develops the underlying software required for self-driving vehicle deployment. 

The company’s $1.05bn funding round in May last year defied an otherwise dreary period of investment in British businesses and its commitment to London as a “tech superpower” – in the words of CEO Alex Kendall – will provide comfort to a government desperate to keep the UK competitive in AI and autonomous driving. Wayve has received funding from the likes of SoftBank, Uber, Microsoft and NVIDIA. 

Synthesia 

Valuation: $2.1bn 

Synthesia, the developer of human-like AI avatars, held the honour of being Britain’s most valuable generative AI company…for about two weeks. Though its crown was taken by ElevenLabs, Synthesia remains the top company for what it does. 

Users can generate video presentations by simply inputting a script. Synthesia’s software will generate an uncannily human-esque speaker with increasingly lifelike body language and facial expressions (if you haven’t seen it in action, it is both genuinely impressive and a little terrifying). Investors include Google Ventures, Accel and MMC Ventures. 

Quantexa 

Valuation: $1.8bn 

Quantexa develops AI analytics tools are used to detect and prevent financial crime, an area of increasing importance with fraud costing the UK billions. It achieved its impressive valuation following a $129m Series E round in 2023. 

The company has been keen to establish itself as a global player, becoming the first British company to join the World Economic Forum’s Unicorn Community in January.   

Stability AI   

Valuation: $1bn 

At the best of times considered Britain’s answer to OpenAI, Stability has more recently been known for its…staffing issues. 

The company rose to prominence off the back of its image and video generating AI models, not unlike Dall-E and Sora. Though its technology is undeniably powerful, between 2023 and 2024, the company bled through senior management.    

The head of its audio team resigned over ethical issues regarding its position on the use of copyrighted material, and not long after it also lost its founding CEO Emad Mostaque, CTO Tom Mason and one of its original developers Tobin Rombach. Last year, the company was able to bring on a big name in AI to its board with the surprise appointment of Terminator director James Cameron. 

Builder 

Valuation: $1bn   

Described by a Microsoft executive has “creating an entirely new category” of AI business, Builder’s platform uses artificial intelligence to develop entire apps at the behest of its users, which includes JP Morgan Chase.   

The Microsoft-backed company has also received a healthy amount of support from the sovereign wealth fund of Qatar, which led its £200m Series D in 2023.   

Tractable 

Valuation: $1bn 

Bringing artificial intelligence to the insurance and disaster recovery industry, Tractable has built a platform trained on millions of datapoints that can analyse images of cars and homes to assess the damages and offer recommendations based on the result. 

Tractable became the UK’s first computer vision unicorn in 2021 courtesy of a $60m investment from Insight Partners and Georgian Partners and has since received additional funding from SoftBank’s Vision Fund II. 

Oxa 

Valuation: $560m – $840m 

Like Wayve, Oxa develops software for autonomous vehicles. The Oxford-based firm has deployed its tech in a number of commercial ventures, including shuttle services in Britain and the US. 

The Google-backed firm also recently set its sights on bringing self-driving technology to industrial logistics through the acquisition of StreetDrone. 

Google DeepMind   

Valuation: $800m 

By the standards of this list, DeepMind is a pretty old company, having been founded in the distant era of 2010. A true pioneer of modern AI, much of the success of the industry in the 2020s owes itself to the work of DeepMind’s researchers and engineers. 

The company received an offer to be bought by Mark Zuckerberg for $800m in 2014 but turned it down in favour of a lower offer from Google and has now become responsible for the nearly all the tech giant’s entire AI offering. As a standalone entity, its value would likely be in the tens of billions of dollars by now. 

In 2023, the DeepMind-made Gemini was launched to take on ChatGPT and remains Google’s flagship generative AI product. 

PolyAI   

Valuation: $500m   

Founded in 2017 as a spinout from the University of Cambridge, PolyAI develops AI-generated voices designed for customer service centres. 

Run by Nikola Mrkšić – a former Apple engineer who helped create the voice assistant Siri – PolyAI’s clients include Volkswagen and Marriott and Ceasar’s Entertainment. The company has been backed by NVentures, the VC arm of NVIDIA.