The UK government has ordered Apple Inc. to build a backdoor to give it access to global user data, in a move that could spark one of the biggest privacy fights in the iPhone maker’s history.

Secret order requires blanket access to protected cloud backups around the world, which if implemented would undermine Apple’s privacy pledge to its users.

Britain demands Apple provide extensive access to encrypted user data, raising privacy concerns. The request, issued under the Investigatory Powers Act 2016, seeks blanket access rather than specific accounts.