Originally Posted by Ludwig II
UK rules limit muzzle velocity, otherwise it needs a firearms certificate. That's not to say that people who go out rabbitng and ratting haven't "fine tuned" theirs.
I've seen that on the forums. There are several online custom airgun sites that are based in UK.
Canada has an even stricter power limit than UK. At least the UK limit is high enough to be useful for small-game hunting.