Someone who just doesn’t get on with their self inflicted, otherwise shitty life within their own patch or ghetto and who keeps cropping up as an indecent and ironic cameo in polite circles.
They gain access to the well ordered and pleasant lanes of middle England by sliding in as mock Middle Englanders. Once ensconced they then un-pack themselves like a virus
and degrade and erode everyone's life, causing havoc as they un-pick the fabric of communities, clubs and charities that do not have tight enough integrity in place. Power Chavs have one minor good use and that is they unwittingly subject the real Middle Englanders to a purity test,
depressingly some fail as they espouse the Power Chavs new, “No nonsense, modern and refreshingly convenient” lifestyle including the interesting, at first, patoir. All Power Chavs have a loud voice, are quite verbose and uncannily know certain parts of the law inside out.
That x really is a Power Chav, have you noticed? They have talked their way onto the committee, changed everything, thrown out all the old time honoured traditions, frightened away the usual volunteers and now resigned in an undignified public outburst leaving the place in a state of total collapse.