Microsoft will switch on Anthropic's Claude models by default for UK Copilot customers on December 9, and Anthropic processes that data in the US.
Richard Speed reported for The Register that any UK organization that has not chosen a setting by that date will have Claude enabled. Administrators can still turn it off. The reporting covers UK customers only.
The mechanism matters more than the model. This is an opt-out arrangement: the feature is on unless someone acts. In a large company, a setting that nobody owns tends to stay at its default, so the practical effect is that Microsoft decides for every organization that does not look. Opt-out defaults are standard for features a vendor wants adopted, which is why they are rarely neutral.
The data location is the sharper edge. Claude requests from UK tenants would be handled by Anthropic in the US, so the data leaves the country. For a team that has promised customers, regulators or its own legal department that information stays in the UK, that is a change worth checking before the date rather than after. For everyone else, it may be a non-event.
There is also a split in responsibility. The model provider is a separate company from the one selling the product, so an organization's data question now involves two vendors, not one. A default-on switch asks admins to sort that out on Microsoft's timetable.
The open question is how many UK organizations have someone assigned to read the setting before December 9, and how many find out afterward.