The US government has walked back a directive that kept Britain from testing new AI models before their release. As of October 11, 2026, the UK’s AI Security Institute (AISI) once again has access to pre-release systems from Anthropic, Google DeepMind, and OpenAI.
The pause lasted just 17 days.
What happened, and how fast it unraveled
On September 24, 2026, the Trump administration asked OpenAI and Anthropic to stop sharing new AI models with the UK’s AISI. The hold was meant to last until a comprehensive US national security review was finished.
That was a sharp break from how things had worked. Under earlier voluntary arrangements, the UK received early access to emerging AI systems so its researchers could probe them before the public did.
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UK AI minister Kanishka Narayan lobbied to reverse the decision. On October 11, 2026, the US reversed its earlier directive, and the UK’s access was restored.
The restored access covers three of the biggest names in the field: Anthropic, Google DeepMind, and OpenAI. Notably, Google DeepMind was not named in the original September request, which targeted OpenAI and Anthropic specifically.
The Claude Mythos 5.1 wrinkle
The pause had at least one visible side effect. Anthropic released its Claude Mythos 5.1 model exclusively to US organizations during the interim period.
Background: why the UK has a seat at the table
The AISI was set up after the 2023 AI safety summit. Its core job is to evaluate what advanced AI systems can do and what risks they might pose.
President Trump has argued for encouraging AI development rather than restricting it.
What this means for AI labs, governments, and investors
For the AI labs, the episode is a reminder that voluntary arrangements are only as stable as the political conditions around them. OpenAI and Anthropic were asked to change course on short notice. Anthropic, at least, adjusted a product release to match.
Several questions remain open. It is not clear whether the US national security review has concluded or what it found. It is also unclear whether Anthropic will now expand Claude Mythos 5.1 beyond US organizations, as its interim approach suggested it might.
Watch for whether the restored arrangement gets formalized or stays voluntary. A written framework would offer labs and allied governments more predictability.
Disclosure: This article was edited by Diego Almada Lopez. For more information on how we create and review content, see our Editorial Policy.