No, not that ring around the bathtub and not that stuff that floats on top of ponds. I'm talking about true scum of the earth.
I'm talking about chavs, neds, scallies and the like. "Wossat?", you cry?
Well, if you live in the UK, you probably already know. They're one of the reasons I just had to get out.
To aid your research, here are some resources. Now bear in mind that these are meant to be humourous, and they are to a certain degree - especially the Glasgow one - but this is reality. They are not fabricated. Go to any British town centre and you will run into real-life sewer scum, just like portrayed (in fact, photographed) in these sites and they make life a complete misery for normal, honest, hard-working people.
They would be an ideal subject for reality TV - apart from the fact that any TV crew would be abused, pummelled and have their equipment stolen, broken and (in the case of their TV van) set on fire.
The first site I found (thanks to Francesca) is Chavscum which gives a reasonable overview of the general UK scum but this led me to a few others, most notably Glasgow Survival which had me alternatively wetting myself with mirth and then almost crying as I recalled that this is no joke, these people really exist, really behave like this and really (most worrying) think they look good, especially in their stupid cars.