Um.
Chav, actually originates from the gypsy word 'chavo', meaning little man (although it's had other meanings ascribed to it since attaining popular usage, such as relating to Chatham etc); that's why I don't like the word, when you get the sort of 'chav scum' type sentiments, I'm always brought to mind of the Nazis using similar language towards (amongst others) romany gypsies (having learn of its origins).
Ned, although backronymed to mean 'Non Educated Delinquient', originates from the 'Teddy boy' (rocker) gangs of the 50s, and I would guess also references the old-style 'razor' gangs as well.
No, i'm not english. I'm from the cold-but-nice place that borders it on the north.
@Aldo, whats a Chav?
Essentially... usually lower-class (i.e. poor, from socially deprived areas, with little educational or future prospects), aged around 14-20 (roughly), like to wear things like kappa tracksuits, burberry caps, and fake gold jewellry, tend to hang about on the streets drinking cheap highly alcoholic bevvy (buckfast, MD20/20, etc), usually are regarded as being quite rude/intimidating/loutish and having taste inverse to the amount they shout about, and big fans of Vauxhaull Novas with fake added exhausts, superfluous spoilers, hilarious big engine grills, and black tinted windows.