UK regains pre-release access to US AI models after White House reversal

Britain’s AI safety testers are back in the room. The UK’s AI Security Institute (AISI) can once again evaluate advanced models from major US developers, including OpenAI and Anthropic, before those models reach the public. The shift follows a reversal by the Trump administration on October 11, 2026. It restores a voluntary arrangement that Washington had effectively paused only weeks earlier. What changed, and why it matters The story starts in September 2026. That month, the White House asked OpenAI and Anthropic to hold back new models from AISI until US reviews had been completed. The result was a sequencing rule. American officials got first look, and British evaluators waited in line until Washington signed off. The directive had real consequences. Anthropic restricted the release of its Claude Mythos 5.1 model to US organizations, based on the White House request. The October 11 reversal unwinds that. US developers can again share pre-release models with AISI under the voluntary access setup that existed before the September directive. That means British testers can probe models for safety risks and potential misuse ahead of launch, rather than after the fact. The lobbying b...