White House asks OpenAI and Anthropic to hold new models from UK testers until US review

U.K. leaders are calling for a shared set of global principles, even as the White House seeks first access to new models for testing. The White House has asked OpenAI and Anthropic not to share their new artificial intelligence models with the U.K. government’s testing agency until the models have gone through testing with the U.S. government, according to a person familiar with the matter and a senior U.S. administration official, both of whom were granted anonymity to describe the request. The request, which came from the Office of the National Cyber Director, puts companies in the difficult position of having to choose between withholding their models from U.K.’s AI Security Institute – one of the most well-resourced government testing agencies in the world which previously enjoyed privileged early access to models – or risk upsetting the Trump White House.

The senior administration official said the White House wants the U.S. to review the models and take steps to make sure U.S. systems are secure before the models are shared with U.S. partners. The White House did not immediately respond to a request for comment. Anthropic appears to have agreed to the request, so far.

The company did not provide its Claude Mythos 5.1 model to U.K. AISI, saying in its announcement that the model was “only available to a set of U.S. organizations.” “We’re coordinating with the U.S. government to expand access to a broader set of domestic and international partners as quickly as possible,” an Anthropic blog announcing the model reads. Anthropic declined to comment for this piece.

In a letter to a U.K. parliamentary committee earlier this month, AISI Director Henry de Zoete acknowledged the lack of access to Anthropic’s model, but said: “We maintain strong relationships with all frontier AI developers and continue to have prerelease access to some of the world’s most capable models,” pointing out that it tested OpenAI’s GPT-6 Astra model ahead of release. OpenAI did not immediately respond to a request for comment. The Trump administration’s request comes as the White House tries to determine how the government should handle powerful, new AI models that have hacked into outside entities during testing - including, as revealed yesterday, an Australian government website.

It also comes as former engineers and leading officials from major AI companies warn of possible catastrophe if their models are left to advance unchecked. Created in 2023, the U.K.’s AISI has established close links with leading AI labs, routinely testing their latest models ahead of public release on a voluntary basis. The U.K. government has made AISI’s expertise and model access a central part of its domestic response to AI safety concerns, as well as its pitch to lead work on a global agreement on AI.

Prime Minister Andy Burnham this week said AI will be “at the heart” of the country’s G20 presidency next year. But AISI’s privileged access to frontier models from leading American labs is under pressure from the Trump administration’s insistence that the U.S. government get first access to emerging systems. The U.K. has sought to downplay any clash, with Burnham saying at the U.N.