Anthropic Refuses to Grant the UK AI Safety Institute Access to Its Latest Model

According to Sina Finance, Anthropic declined to submit its latest model, Claude Mythos 5.1, to the UK’s AI Safety Institute (AISI) for testing prior to release, as the model is currently accessible only to vetted U.S. institutions. This move has raised concerns within Whitehall and at AISI, with UK national security officials fearing it could set a precedent preventing AISI from accessing future cutting-edge models. Analysts suggest this decision may be linked to the U.S. government’s increasingly strict export controls on the AI industry—previously, the U.S. government has imposed export restrictions on Anthropic’s Mythos and Fable models, prohibiting their use by foreign nationals. Anthropic declined to comment, stating only that it is “coordinating with the U.S. government to expand model access to more domestic and international partners as soon as possible.”