Microsoft will enable access to Anthropic’s Claude models by default for UK Copilot tenants from December 9, The Register reported, and administrators who leave the setting untouched will be opted in, though they can disable it. Anthropic acts as a Microsoft subprocessor and processes the relevant data in the United States, according to Microsoft’s documentation, and Claude is already on by default for most commercial cloud customers outside the European Union, the European Free Trade Association and the UK. UK tenants are not covered by Microsoft’s EU Data Boundary, which is why the switch is being flipped for them, and Microsoft is also retiring the setting that restricts Claude access to Microsoft 365 alone.
Microsoft switches on Claude by default for UK Copilot tenants
From December 9, UK Copilot tenants whose administrators have not chosen a setting will have Anthropic's Claude models enabled by default, with the data processed in the United States.
Why it matters: The UK sits outside Microsoft's EU Data Boundary, so the default quietly moves UK tenant data to US processing unless administrators opt out by December 9, a compliance decision many organisations will now have to make actively.
Data as of The Register report of November 10, 2026, read in full; the change and the December 9 date are stated in Microsoft's own administrator documentation, which the report cites. Single source. Developing item.
Sources
- Microsoft is giving Claude the keys to UK Copilot tenants by default - The Register - 2026-11-10