Microsoft will enable access to Anthropic's Claude models by default for UK Microsoft Copilot tenants next month, giving administrators a deadline to decide whether US-based processing fits their compliance requirements, The Register reported on Tuesday.

From December 9, UK tenants whose administrators have not already chosen a setting will have Claude access enabled. In this arrangement Anthropic operates as a Microsoft subprocessor, and Claude models are already on by default for most customers in Microsoft's commercial cloud.

Microsoft's documentation states that Anthropic processes the relevant data in the United States. Microsoft is also retiring the setting that restricts Claude access to Microsoft 365 alone.

For UK Copilot admins this is a practical deadline, not just a product note: review the access settings before December 9 if your organisation has rules about where Copilot data is processed.