The UK should be pretty safe. No serious volcanoes, earthquakes, or hurricanes, or fierce or poisonous wild animals. We have serious tornadoes but they hardly register on most people's radar. We have flooding but that ought not kill you nowadays. We have occasional cold weather but nothing that can't be dealt with easily. We have terrorists, but they aren't statistically significant. The biggest cause of death, other than old age, is probably traffic.
If you read some of the things I've been privy to reading about the threat of terrorism in England...you wouldn't want to live there. Heritage Foundation has wrote a few interesting things for the Weekly Standard news magazine on the subject in the past.
Let's just say that one phone call would mobilize two generations of domestic born lunatics to spread blood across the London area.
I hope I'm wrong, though.
Sadly, I suspect that phone call would work almost anywhere in this day and age.
It often surprises me that folks tend to be acclimatized to the threats in their region and adjust accordingly.
I was once in Pasadena, California during a very minor thunderstorm (maybe 1 or 2 lightning strikes per 5 min.). The local folks were freaking out, but three days latter when a small shake happened in the earth I was outside before the door automatically closed. (The locals were laughing, but you would be shocked how fast a fat man can run!)
Many from California would never think to live on the Gulf Coast due to hurricanes, but I haven't noticed a mass migration from the coast recently.
I guess if one is making a final move to an area this study works, but I look at some threats like a pin prick on the map and some like a shotgun blast. Geographically tornados damage a relatively small area compared to earthquakes and hurricanes. I think I will just stick with what i've got.