Being prepared for common occurrences like fire, theft, accidents on the home is very sensible indeed.
However individuals trying to prepare for more unexpected outcomes like mass pandemics, nuclear war and so on, I don't really understand.
The reason is, there is always a bigger catastrophe that the universe can throw at us. At any time an extinction level event can occur, be that super-volcanos, space rocks or gamma ray bursts; you can have the bunker stocked with a lifetime supply of corned-beef and clean air, either way; you aren't going to make it.
We all need to face up to the reality that we aren't immortal, we are going to die, so is everyone we know, and in a few generations (assuming there are any more generations) we will be utterly forgotten.
Even at a species level, we can be absolutely 100% sure we wont survive indefinately. It's not something to worry about, it's just the nature of our reality.
Some people may find that depressing, but I view it as freeing; dont worry about what you cant control.
That being said, I hope you have a good flight and a nice visit here in the UK, oh and bring an umbrella!
Everyone has their own ideas I guess and some like to be prepared for things as it gives them a feeling of security whether their hopes of survival are good or not. Most people are woefully unprepared for anything. Taking the we're going to die of something approach is one way to go I suppose. I know a few like that and the other type also; The government will look after us approach. Maybe they will, maybe the government might be the actual problem in the first place.