UK Seeks Exemption from US Ban on Anthropic’s AI Models

Downing Street is pressing the White House for an exemption from a sweeping American export ban that has stripped British users of access to Anthropic’s most advanced artificial intelligence.

After President Trump blocked foreign access to Claude Fable 5 and Mythos 5, two versions of the company’s newest and most capable model, No 10 officials began working the phones across the US administration in search of a UK carve-out. So far the lobbying has produced little. Officials in Washington remain wary that the technology carries security risks once it travels beyond America’s borders.

“There is an effort to seek an exemption, but there are security issues to consider,” said one figure with knowledge of the talks.

For Britain’s businesses, the episode is a sharp lesson in how quickly access to critical infrastructure can be switched off by a decision taken thousands of miles away. The same Mythos model now at the centre of the row had already set off crisis meetings among finance ministers and central bankers earlier this year over its uncanny ability to surface vulnerabilities in widely used software.

The US Department of War has taken the toughest line of all, tearing up a defence contract with Anthropic. The White House, by contrast, had been viewed as the more pragmatic actor — until officials concluded the company had failed to allay their concerns about the new model and moved to drastic action.

Anthropic announced on Friday that all foreign nationals, including its own overseas employees, would be barred from using the model. The company said the government believed there was a method of “jailbreaking”, or bypassing, Fable 5’s safeguards.

“To date, the government has only given us verbal evidence of a potential narrow, non-universal jailbreak, which essentially consists of asking the model to read a specific codebase and fix any software flaws,” Anthropic said. The firm added that it had complied with the legal directive but disagreed with the decision to recall a model relied upon by hundreds of millions of people on the basis of a “narrow potential jailbreak”. “If this standard was applied across the industry, we believe it would essentially halt all new model deployments for all frontier model providers,” it said. Because it could not quickly build nationality-based access controls, the company pulled both Fable 5 and Mythos 5 for users worldwide, Americans included.

The tone from the Pentagon has been unmistakable. On Saturday, Pete Hegseth, the US secretary of war, posted on X: “Three months ago, the Department of War kicked Anthropic out of our building, forever. Every passing day proves why that was the right move.”

For ministers, the affair has crystallised a long-running anxiety about Britain’s dependence on a handful of American AI suppliers. Kanishka Narayan, the UK government’s AI minister, said the ban underlined the importance of building “sovereign AI capability” at home.

“This week, the most advanced AI in the world was cut off for everyone in Britain,” he said. “Not by us, but by a decision taken in another country. We treat every other threat to our sovereignty with deadly seriousness, but we haven’t learnt to treat this one the same way.”

That argument is no longer abstract. The government has already stood up a £500m Sovereign AI fund to back home-grown developers, and private capital is following, with a £1bn push to build Britain’s first fully sovereign AI infrastructure network now under way. The Anthropic ban hands those efforts a powerful new justification, and a warning to every UK firm that has wired a foreign model into its products and processes.

The diplomatic test comes quickly. Sir Keir Starmer is due to meet Trump this week at the G7 summit, where the carve-out is expected to feature in the conversation. For the thousands of British SMEs that have built workflows, customer-service tools and software pipelines around frontier AI, the practical message is blunt: resilience now means knowing exactly which of your suppliers could be switched off overnight, and what you would do the morning it happened.

Amy Ingham

Amy is a newly qualified journalist specialising in business journalism at Business Matters with responsibility for news content for what is now the UK’s largest print and online source of current business news.

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