The founders are quietly deciding UK isn't where ambition gets rewarded and what that's actually costing them.
It's a pattern increasingly described as the UK tech brain drain, and Barney Hussey-Yeo's story shows how it usually starts by accident, not design.
Literally, that was the feature. Cleo, the chatbot he launched from his London flat in 2016, would look at your bank balance and take the mick out of your spending like a mate who'd had one too many and lost all sense of tact. It was cheeky, very online, very British. He built it for people just like him — twenty-somethings in the UK, drowning in overdraft fees, tired of being patronised by their banks.
Six years later, Cleo didn't have a single customer in Britain. The whole product had quietly switched itself off at home while it went on to conquer somewhere else entirely.It's as clean an illustration of the UK tech brain drain as any headline could offer.
So here's the question worth sitting with before we go any further: If a company built for British consumers ends up abandoning Britain altogether, what does that say about the market it was built for?
There's a popular version of this story
British founders are deliberately bypassing London for bigger markets like San Francisco, Dubai or Singapore.
The founders themselves tell a different story, since most didn't set out to leave. They naturally found themselves pushed there as Britain became a harder place to build. It's what makes the UK tech brain drain harder to fix than a simple exodus, as nobody's leaving on purpose.
Cleo: an accident that became a verdict
Hussey-Yeo will tell you himself that none of this was the plan. Cleo's early ambition was 40 countries, launched from a UK-first playbook. Then Covid hit, the hiring freeze came, and a team of 40 people simply couldn't run three markets at once. So they picked the one where the numbers actually worked. America was growing. Britain wasn't. That was it. That was the whole strategic masterplan.
"I think it's kind of crazy that people create UK-centric consumer companies," he told Sifted in 2023, with the particular bluntness of someone who's already made the mistake. "It makes absolutely no sense, given how small the market is versus the US." Starting Cleo as a UK-only product, he says now, was "probably a bad call" — one he made at 25, before anyone had told him better.
Here's the fun fact that tells you how far this went: By the time Cleo shut its UK product in 2022, its American user base was roughly the size of Monzo's entire UK customer base - a remarkable outcome for a product originally built for Britain.
By 2024, Hussey-Yeo had become openly critical of the UK's startup environment. Writing in Fortune, he argued that moving Cleo to the US "went beyond market size - it was a stark recognition that Britain stifles ambitious tech companies."
Cleo now runs at more than $300m in annual recurring revenue, with roughly 500 staff spread across London, New York and San Francisco. It's edging back into the UK market this year, a decade late to its own home crowd. We'll believe the full comeback when we see it.
Hussey-Yeo isn't the only proof point, either. Mustafa Suleyman built his first great British success story, DeepMind, in London - a marquee product of the London tech scene at the time then sold to Google in 2014 for a reported £400m, one of the biggest AI exits Europe had produced.
He knew what it took to build something serious in Britain, because he'd already done it. So when he started his second company, Inflection AI, in 2022, he didn't test his luck a second time. He built it in Palo Alto, with Silicon Valley capital behind it from day one. The first time, London worked well enough. The second time, once he actually had the choice, he didn't choose it.
Entrepreneur First: London builds them, San Francisco keeps them
If Cleo is one founder's accidental exile, Entrepreneur First has turned the same instinct into a business model.
EF is the London-founded "talent investor" - long a fixture of the London tech scene - that takes ambitious people who don't even have a company yet, pairs them into founding teams, and backs them, has reached a similar conclusion.
Its new San Francisco "Bridge" programme is built around a simple observation: startups relocating to the Bay Area reach commercial traction far faster than those staying in Europe. It's the UK tech brain drain formalised into a pipeline.
"American customers are very fast in terms of procurement experimentation," CEO Alice Bentinck told Sifted in October 2025. "They have very deep pockets." EF has since closed its France and Germany cohorts in favour of a San Francisco "Bridge" residency, and every startup reaching EF's US demo day is now expected to incorporate there and complete the so-called Delaware flip — the moment a British-born company legally stops being one.
Founder Zain Hussain now pitches Trident AI to Bay Area investors rather than London ones because that's where Entrepreneur First believes the biggest opportunities now lie.
Bentinck herself hasn't moved EF's headquarters, and she's careful not to sound like she's given up on Britain. "I'm European, I'm British, and I want the ecosystem here to do really well," she told Sifted in August 2025. But she's just as clear-eyed about what she's watched happen: European founders, she says, "underestimated the impact of giving teams access to American customers" — and once they've had it, most don't come back.
We think that's the more honest headline than "founders going global." It's London producing the talent and Silicon Valley banking the returns. It's one more page in the UK tech brain drain playbook.
Dubai: when it's really just about the tax bill
Not every departure has a customer-speed story behind it. Some of it is a lot more mundane than that.
Since late 2024, tax advisors across London have reported a sharp rise in enquiries from UK founders and investors about relocating to the UAE — as much as 15–20% of new business at one firm, Founders Law, by May 2025.
It's a small but telling slice of the broader founder relocation trend running through this piece. The trigger wasn't inspiration, it as capital gains tax rises, the scrapping of Entrepreneurs' Relief, and a jump in employers' national insurance.
"There is now a ceiling on what the most ambitious founders can achieve here," Hussey-Yeo told Sifted at the time — the same complaint, almost word for word, surfacing in two entirely separate conversations, which tells you how widely shared this feeling is among Britain's most visible founders. "A shortage of growth-stage capital, an onerous regulatory environment and a broken London Stock Exchange leave virtually no path to scale or list generational companies domestically."
But the advisors arranging these moves are quick to puncture any romantic "building globally, on purpose" framing. Bhavika Nesbitt of Wilson Partners told Sifted that most people relocating to Dubai are doing it for personal tax reasons, not to relaunch their business abroad — "they continue to operate their UK businesses, but are able to do so remotely." And Dubai's own converts admit the destination has real drawbacks: a thin early-stage VC scene, and an eleven-hour time difference from the market most of them actually need, which is San Francisco.
So: not a growth strategy, but a tax return with a better climate attached. Add it up, and it says as much about the UK startup environment right now as any policy paper could.
Our take
Taken together, these stories suggest founders aren't chasing glamorous global opportunities as much as responding to incentives. Tax policy, customer demand, growth-stage capital and public markets, including the London Stock Exchange, increasingly point away from Britain. It's the UK tech brain drain in miniature, not one decision, but many small ones pointing the same direction.
Worth flagging, briefly, before we go: this isn't the only founder relocation story running through UK tech right now. In the same period Hussey-Yeo was writing about feeling stifled, well over a third of the UK's hundred fastest-growing companies had a foreign-born founder or co-founder, according to analysis by The Entrepreneurs Network - people moving into Britain to build, not out of it.
That's a current running the other way entirely, and it deserves its own piece rather than a footnote in this one.
For the founders leaving, though, the pattern holds. So we'll leave you with the harder question, not the tidy one: it isn't whether British founders are winning by building abroad on purpose. It's why the ones who are winning abroad mostly never planned it that way, and what it would actually take for staying to start feeling like the deliberate choice again.Until then, the UK startup environment will keep making that decision for them.
This piece draws on public statements, interviews and reporting by Sifted, Fortune and Forbes; EP+ has not conducted direct interviews with the founders named.
Also read: Taking Your UK Startup to the US: The Brutal Honest Truth
Sources: Sifted, Dec 2023 — Cleo/Hussey-Yeo US pivot Sifted, 2024 — Cleo $150m ARR and UK return plans Fortune, Nov 2024 — Hussey-Yeo op-ed Wikipedia / Greylock / Microsoft Blog — Mustafa Suleyman, DeepMind and Inflection AI timeline Sifted, May 2025 — UK founders relocating to Dubai Sifted, Aug 2025 — Alice Bentinck interview Sifted, Oct 2025 — Entrepreneur First's Silicon Valley pivot The Entrepreneurs Network / Beauhurst — foreign-born founders in UK's top 100 fastest-growing companies
