I agree with Impreza09 here, it's one of the most annoying things, especially on a dual carriageway, not so much of a pain on a 3 or 4 lane stretch as cars still have a lane or 2 to drive on, but on a 2 laner it's particularly frustrating.
I know that there are quite a few parts of certian british roads where this practice is banned, and there were rumours of a possible nationwide ban on this in the UK, but wheather that ever came to anything i dont know.