Tell the UK government that!! ...although blocking the thing has done fearsome tweak all in reducing P2P traffic, a large amount of which is unlawful.
There are legitimate uses for torrents; an increasing number of development companies use them while pushing patches out or for trial versions of stuff: since the torrent option can be quicker and is inherently safer since if you lose connection or if the site goes down (quite common on patch release dates); you can restart from where you stopped rather than need to download the whole file again. That is a small minority of torrent use admittedly; but its a good reason not to shout at someone who has a utorrent icon on their desktop or a transmission icon in their dock or something. Pirate bay isn't technically illegal because of the interesting details of Swedish copyright law; but you can hardly say that the vast majority of its files aren't copyright infringing in some way.