To be clear, this is a part of a government strategy to get people generally more prepared for temporary issues over the next 3 years or so, and to bring the UK more in line with other regional countries such as France.

There is no imminent threat to the UK that has been disclosed.

When I lived in Tillicoultry in Scotland some 50 years ago we had a 'snow pantry' because getting snowed-in for a week wasn't uncommon in the Winter. Build it up over Summer and use it if you need it. This is the same thing.