Apple will no longer offer customers in the UK its most advanced, end-to-end security encryption feature for cloud data storage - following a row with the government.
The Advanced Data Protection (ADP) tool is an optional feature which means only account holders can see things like photos or documents that they have stored online. Apple itself does not have access to the data.
However, the UK government reportedly requested the right to see the data earlier this month.
In response, Apple has removed the tool from use in the UK.
Source and further reading:

Apple removes advanced security tool over UK government row
ADP is a tool offered to Apple customers that means only account holders can see things like photos or documents that they have stored online. Apple itself does not have access to the data.