The British government has thrown its weight behind one of the most ambitious artificial intelligence ventures ever launched in the United Kingdom, joining a record-breaking $1.1 billion (£810 million) seed funding round for London-based Ineffable Intelligence.
The startup, founded in late 2025 by Professor David Silver, one of the world's most prominent AI researchers and the former head of reinforcement learning at Google DeepMind, has emerged from stealth with a post-money valuation of $5.1 billion, making it one of the most highly valued early-stage companies in European history.
The round, Europe's largest seed financing to date, was co-led by United States venture capital giants Sequoia Capital and Lightspeed Venture Partners. It also drew participation from NVIDIA, Google, Index Ventures, DST Global, EQT, Evantic, Flying Fish Ventures, BOND Capital, and the Wellcome Trust.
Government backing for British AI sovereignty
The UK government's involvement comes through two channels: the newly established Sovereign AI Fund — a £500 million ($678 million) vehicle designed to act like a venture capital fund with the muscle of the state behind it and the British Business Bank, the government's economic development bank.
The British Business Bank has committed $20 million to Ineffable Intelligence, adding to an AI portfolio that includes nine investments over the past twelve months, among them autonomous vehicle company Wayve and conversational AI firm PolyAI. The Sovereign AI Fund is co-investing additional capital alongside the Bank's commitment.
Science and Technology Secretary Liz Kendall hailed the investment as a landmark moment for the UK's AI ambitions.
"Sovereign AI is our bet on Britain, we believe in this nation's entrepreneurs and innovators and we are backing them to seize the benefits of AI for the UK," Kendall said in a government statement. "This investment in Ineffable will support a company at the very frontier of AI, with the potential to transform entire sectors, underlining our determination to ensure that the UK isn't just an AI taker but an AI maker."
AI Minister Kanishka Narayan added: "David Silver is one of the world's foremost AI leaders, now taking one of the world's most innovative approaches to frontier AI. I am delighted that he is doing so right here in the UK, backed by the full support of the British state."
A 'superlearner' that learns from experience
Ineffable Intelligence is pursuing what its founder describes as a fundamentally different approach to artificial intelligence. Rather than training models on vast quantities of human-generated data scraped from the internet, the method underlying systems like ChatGPT and Google's Gemini, the company is building what Silver calls a "superlearner": an AI that discovers knowledge entirely through its own experience.
The company focuses on reinforcement learning, a branch of AI in which models learn through trial and error, interacting with their environment, testing ideas and improving over time, more like humans do. Silver's previous work in this field includes some of the most significant breakthroughs in modern AI: AlphaGo, the first system to defeat a human world champion at the ancient Chinese game of Go; AlphaZero, which mastered chess, shogi and Go from scratch; and AlphaFold, which revolutionised protein structure prediction.
"Our mission is to make first contact with superintelligence," Silver said in a statement. "We are creating a superlearner that discovers all knowledge from its own experience, from elementary motor skills through to profound intellectual breakthroughs."
The company's mission statement goes further, declaring that "if successful, this will represent a scientific breakthrough of comparable magnitude to Darwin".
A brain drain that fuels a startup boom
Silver is one of several former top researchers at Big Tech companies who have left to launch their own AI labs in recent months, with investors funnelling billions of dollars into the ventures.
Last week, the Financial Times reported that Recursive Superintelligence, founded by former DeepMind engineer Tim Rocktäschel, was raising up to $1 billion. In March, **AMI Labs** announced a $1 billion raise, months after its founder, Yann LeCun, announced he was leaving his role as Meta's AI chief. In the past year, former staff at OpenAI, DeepMind, Anthropic and xAI have also raised hundreds of millions from investors for months-old ventures.
Ineffable Intelligence has assembled a team of fellow DeepMind alumni, including Wojciech Czarnecki, Lasse Espeholt and Junhyuk Oh, as its executive team.
'Built in the UK — and that matters'
Josephine Kant, Head of Ventures at the Sovereign AI Fund, offered a ringing endorsement of the company's British roots.
"Very few founders in the world could credibly set out to build a superlearner, a system that discovers new knowledge from its own experience, rather than ours," Kant said. "David is one of them. From AlphaGo to AlphaZero to AlphaProof, he has spent nearly two decades turning reinforcement learning from a research idea into the results the rest of the field builds on. Ineffable is being built in the UK — and that matters."
Charlotte Lawrence, Managing Director of Direct Equity at the British Business Bank, described Silver as "a generational talent who has consistently been on the cutting edge of AI development". She added: "Ineffable Intelligence has the potential to produce a paradigm shift in our scientific and technology landscape, and we are incredibly excited to be supporting him and his team in this endeavour."
George Mills, Investment Director at the British Business Bank, emphasised the strategic importance of keeping such ventures on British soil: "Ineffable Intelligence is aiming to address one of the most significant opportunities within AI, superintelligence, which has the potential to open new frontier applications including in advanced problem solving and new product development with relevance across sectors. The UK produces world-class AI talent, and we are pleased to back strategically important businesses to scale and stay in the UK."
No product, no revenue — but billion-dollar backing
Despite having yet to release a product, generate any revenue, or publish a detailed roadmap for what it intends to build, Ineffable Intelligence has secured backing that would be the envy of established technology companies.
The round's scale reflects the extraordinary confidence investors have in Silver's track record and the potential of reinforcement learning to unlock new frontiers in AI. The company now ranks among the most valuable early-stage startups in Europe, with a valuation that exceeds that of many listed technology firms.
The investment also marks a significant milestone for the Sovereign AI Fund, which was launched earlier this month with the explicit aim of helping the UK's most promising AI startups grow, scale and succeed from Britain. This is the Fund's second direct equity investment since its launch.
With the backing of the British state and some of the world's most powerful technology investors, Ineffable Intelligence now has the resources to pursue what its founder calls "the greatest inventions in human history". Whether it succeeds remains to be seen, but the UK has made clear it intends to be at the centre of the attempt.