Microsoft turns on Claude by default for UK Copilot users

How it works

An AI assistant inside Microsoft Office that helps UK workers write documents and analyse spreadsheets.

1. 🔧Companies leave Copilot settings unchanged
2. 🔓On 9 December, Claude switches on automatically
3. 💬Workers get Claude help inside Word and Excel
4. ⚙️Admins can still block it with a policy change

What you could do with it

• A UK worker could use Copilot inside Word or Excel with Claude as the default AI model, getting help writing documents or analyzing spreadsheets without asking IT for anything ¹.
• A UK company administrator could enable or disable Claude across Copilot, Copilot Researcher, Copilot Studio, Power Platform, and Microsoft 365 apps for all staff through a single policy setting ¹.

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An exampleInvented to explain it

Priya drafting a report in Word

PriyaCan you summarise these meeting notes into bullet points?

ClaudeSure! Here are the key points from your notes...

PriyaMake the tone more formal for the board.

ClaudeDone. I've rewritten it in professional language...

PriyaThanks, that's much better.

She sent the polished version without ever contacting IT.

The new default

From 9 December, any UK organisation that has not changed its settings will automatically have Claude turned on inside Copilot ¹. Administrators can still switch it off before that date . Leaving the setting alone counts as opting in .

Claude was already active by default for most of Microsoft's commercial customers worldwide. The EU, the European Free Trade Association and the UK had been the only holdouts ¹. Microsoft now says the change brings the UK in line .

"This affirms Microsoft's commitment to offering choice between leading AI models while maintaining enterprise-grade security and compliance," the company wrote ¹.

Anthropic, the San Francisco firm behind Claude, operates as a Microsoft subprocessor — meaning it processes customer data on Microsoft's behalf under its contracts and supervision ¹². That means Microsoft remains responsible for how the data is processed, even though Anthropic runs the model .

Where it applies

The change covers Claude inside Copilot, Copilot Researcher, Copilot Studio, the Power Platform and Copilot features in Microsoft 365 apps such as Word and Excel ¹. Microsoft is also retiring an older setting that restricted Claude to Microsoft 365 apps only .

Not every Claude model comes along for the ride. More powerful variants like Claude Fable 5 and Claude Mythos 5 are disabled by default across the board ¹. Anthropic keeps data from those models for up to 30 days, so administrators must give separate permission to enable them .

Data rules and US ties

According to Microsoft's documentation, Claude models in Copilot sit outside Microsoft's EU Data Boundary — the set of rules keeping certain data within Europe ¹. They are also excluded from in-country processing commitments . Since the UK is not part of the EU Data Boundary, the data for UK Copilot users using Claude gets processed in the US through Anthropic .

This change arrives during the same week Anthropic rolled out Claude Sheets alongside other office applications that directly rival Microsoft's own suite ¹.

The wider picture

A new report from the Institute for Public Policy Research (IPPR) highlights how deeply the UK public sector relies on American technology ¹. Of the £19.2bn the UK government spends with its 150 largest tech suppliers, only about £1 in every £6 stays with British firms once ownership and resellers are taken into account . The US receives the biggest share at £9.2bn .

NHS England's Copilot rollout reached 505,000 staff under a national licensing deal signed in June 2023, well before Copilot was generally available ¹. The IPPR report urges the UK government to act as a single buyer when purchasing technology and to make it easier for departments to switch providers . The government has already committed £500m to a Sovereign AI Fund .

UK admins who wish to leave Claude turned off inside Copilot must make that adjustment by 9 December ¹.

Corrections and updates

• Corrected on 11 November 2026. An earlier version implied NHS England staff would immediately benefit from Claude-enabled Copilot via their existing national licensing deal; the source only notes the deal existed separately and does not confirm automatic Claude benefits. A prior caption described a screenshot from learn.microsoft.com showing subprocessor settings for Anthropic; that visual was removed.

Key facts

• Claude is now on by default for UK Copilot users from 9 December
• Administrators can still turn Claude off or opt into advanced models
• Claude data is processed in the US through Anthropic as a Microsoft subprocessor
• Advanced Claude Fable 5 and Claude Mythos 5 models stay off by default
• Claude applies across Copilot, Researcher, Studio, Power Platform and Microsoft 365

Sources

1. Claude goes on by default for UK Copilot users from 9 December — thenextweb.com
2. Claude models from Anthropic in Microsoft Online Services