Shotguns and bolt-action rifles are licensed in the UK. So are black-powder weapons (mostly muzzle-loaders for re-enactment). Air guns are also allowed, in some categories without a license. More here:

http://en.wikipedia.org/wiki/Gun_politics_in_the_United_King...

Note that firearms licenses were pretty much non-existent in Sir Robert Peel's day, and as late as the mid 1980s it was possible to possess an AK-47 or similar (as long as the selector didn't permit burst firing). In spite of which, most police went (and preferred to go) unarmed.