Why is it now being withdrawn from the UK?

It was reported earlier this month that the UK Government had made a request to Apple, under the Investigatory Powers Act, to get broad access to encrypted files uploaded to iCloud, including those secured by end-to-end encryption under ADP.

In order to provide such access, Apple would have to create a security "backdoor" - a new key that would allow the Government to get around the encryption and access the files.

However, Apple has said publicly on numerous occasions in the past, including in its statement on Friday about ADP, that it would not create a backdoor and never will.

The company argues that once a backdoor has been created, it could easily be accessed and used by bad actors, breaking its encryption systems and therefore leaving iCloud users around the world vulnerable to data breaches.

So in response to the Government's request, rather than comply and create a backdoor, Apple has chosen to withdraw ADP from the UK instead.

- Why did the Government want access to encrypted files?

Government, police and security services, and online safety charities have argued for some time that end-to-end encryption is being used by criminals such as terrorists and child abusers to more easily hide their activities online, and has hampered efforts to catch them.

The Government's request to Apple was an attempt to force the firm to break its own encryption systems, and allow police and security services to more easily access such data when needed.

- What does the removal of ADP mean for UK users?

For many users, very little will actually change as ADP was opt-in and only those who had actively chosen to turn it on in the first place have been using it.

Apple said those already using it will see it withdrawn over time, but it can no longer be turned on for anyone wanting access in the UK now.

But even without ADP in place, Apple said more than a dozen iCloud data categories are still end-to-end encrypted by default, including health data and its password management system, iCloud Keychain.

In addition, Apple said its communications services, such as iMessage and FaceTime, remain end-to-end encrypted globally, including in the UK.

However, cybersecurity experts have warned that this has ultimately made UK users less secure, as they have lost access to a higher level of data protection that will remain available to users elsewhere.