The White House asks OpenAI and Anthropic to hold their newest models back from UK testers
Politico reported that the White House asked OpenAI and Anthropic to withhold their newest models from the UK AI Security Institute until a US-led security review is complete, with Anthropic's Claude Mythos 5.1 restricted to US organisations and OpenAI's GPT-6 Astra also named; OpenAI did not comment. AISI director Henry de Zoete acknowledged in a letter to Parliament that the institute lacked access to Anthropic's latest model. The request follows President Trump's September 22 statement that "the United States totally rejects any attempt to construct a globalist scheme to control artificial intelligence." The US counterpart body, CAISI, has had no permanent director since Chris Fall left in July 2026 and is run by acting head Arvind Raman.