UK Businesses Sound Alarm as US Slaps Export Controls on Anthropic's Top AI Models

A Three-Day-Old Launch Goes Dark

Anthropic publicly launched its most advanced AI models, Claude Fable 5 and Mythos 5, on 9 June 2026. Just three days later, on the evening of 12 June, Commerce Secretary Howard Lutnick issued an "Is Informed" letter to Anthropic CEO Dario Amodei, invoking the Export Control Reform Act of 2018 to bar any foreign national, whether inside or outside the United States, from accessing the two models.

Because Anthropic could not reliably verify a user's nationality in real time, it was forced to switch both models off entirely for every customer on the planet. "The net effect of this order is that we must abruptly disable Fable 5 and Mythos 5 for all our customers to ensure compliance," the company said.

The Cybersecurity Trigger

The Wall Street Journal reported that the ban grew out of cybersecurity research conducted by Amazon security teams. CEO Andy Jassy reportedly briefed government officials after Amazon researchers found that Fable 5 could be manipulated, through specific prompts, into providing information that could facilitate cyberattacks. Anthropic has called the episode a "misunderstanding," stressing that the research in question was defensive in nature.

Industry Backlash

The restriction has united an unusually broad coalition against it. Executives at Nvidia and Adobe have urged the administration to lift the ban, arguing the limits actually hamper the fight against digital threats. More than a hundred cybersecurity experts signed an open letter to Secretary Lutnick and National Cyber Director Sean Cairncross, warning the ban "has taken the best models away from defenders, created market uncertainty, and risked America's AI leadership without any real risk to justify it."

Because the controls apply equally to allied nations that share intelligence and defence agreements with Washington, the move has strained transatlantic relations. UK businesses have been alarmed by the sudden loss of access, and observers abroad described the order as asserting a broad, unprecedented authority over the technology.

An Uncertain Resolution

Anthropic sent senior technical staff to Washington over the weekend of 14 to 15 June to negotiate with Commerce Department and White House officials. The talks concluded on Monday without lifting the restrictions, after the National Security Agency warned that Fable 5's guardrails could be bypassed.

The company was already locked in a separate dispute with the Pentagon, which designated it a supply chain risk in March. Anthropic said at the time it faced an immediate loss of more than $150 million in annual recurring revenue from Defence Department contracts, with potential losses reaching billions overall. The Bureau of Industry and Security's directive stays in force until formally rescinded, and Anthropic must now apply for individually validated export licences through the government's SNAP-R portal to restore foreign access. It is the first time the Commerce Department has used this particular legal authority against a commercially available AI model.