You'll need them when the zombie holocaust happens.
It's zombie apocalypse. Zombie holocaust would be suggesting mankind getting rid of all of the zombies. In that case, you wouldn't need guns. A zombie apocalypse is when the undead outnumber the living and in that case you probably do need guns
No guns in the UK, at least not legal ones that aren't related to farming or hunting. Knifecrime is huge though, especially in some parts of England.