I really don't see the issue with the government testing emergency alerts on phones. People can disable the feature if they prefer so they don't have to go to all the effort of clicking to acknowledge it 
Countries like Japan regularly use it. While the UK isn't as tectonically active it does make sense to at least make use of the tech incase it's needed. We've had a helicopter hovering above with a loud speaker giving advice in the past, makes much more sense to make use of phones for stuff like this.
Seems another "I'm not a sheep, they're taking control" thing that people jump on
Countries like Japan regularly use it. While the UK isn't as tectonically active it does make sense to at least make use of the tech incase it's needed. We've had a helicopter hovering above with a loud speaker giving advice in the past, makes much more sense to make use of phones for stuff like this.
Seems another "I'm not a sheep, they're taking control" thing that people jump on