US AI giants are planting flags in London at a pace the city has never seen, and in doing so they are turning the British capital into the clearest rival to San Francisco, while making life harder for the homegrown startups they are landing next to.
In the past few months Anthropic has taken office space for 800 people in London’s Knowledge Quarter, roughly four times its current headcount there; OpenAI opened its first permanent UK office; the coding-tool maker Cursor said it will open a London headquarters this summer; Google is moving teams into a new 11-storey building in King’s Cross; and Databricks, Salesforce and the Nvidia-backed video startup Runway are all adding staff or space.
The numbers behind the rush are stark: AI firms signed for 565,000 sq ft of London office space in the first four months of 2026, with another 288,000 sq ft under offer, against 211,000 sq ft in the whole of 2025 and 130,000 in 2024.
Why London, and why now
The pull is talent and money. ‘It’s all about talent,’ Mike Wiseman, head of campuses at the developer British Land, told CNBC, calling London ‘one of the few markets globally’ that can support international scaling.
The city is also one of the world’s main financial centres, giving AI firms what analysts describe as ready access to venture, growth-equity and corporate-development networks as they chase commercial revenue.
The clustering is self-reinforcing: Anthropic’s new base sits in the same Knowledge Quarter as OpenAI, Google DeepMind, Meta, Synthesia and the autonomous-driving firm Wayve. London now hosts more AI companies with 50 or more employees than San Francisco does.
That is the upside the UK government has chased, including through priority-access deals with OpenAI, DeepMind and Anthropic. But there is a catch the boosterish framing tends to skip.
The same well-funded American firms are bidding up the price of the engineers and researchers that British startups need, and Dan Hyde, who runs the executive-search firm Erevena, warns the activity is putting pressure on local startups and making top talent harder to hire.
A founder competing with Anthropic’s compensation budget is not competing on equal terms, and the UK has spent years trying to keep talent like its DeepMind alumni building companies at home rather than feeding the US giants.
None of this is slowing down.
The leasing record looks set to break again in the second half of the year, and the trend points one way: London is cementing its place as the most important AI hub outside the United States. The open question is whether Britain ends up owning a serious slice of that industry, or simply hosting everyone else’s. For now the city is winning the offices, the jobs and the prestige.
Whether it keeps the companies is the harder test, and the one the people doing the work are watching most closely.
