The thing is, I don't see UKIP maintaining their level of support past the next general election. Cameron has shifted rightwards recently, and as the election approaches he will continue to differentiate himself from the Lib Dems. Then, if the Tories lose, they will pick up some of the anti-gov support referred to in the article above. If they win, barring another coalition with the Lib Dems, they will govern more from the right and perhaps offer an EU referendum.

I've elaborated on this here: http://leoleoleoblog.wordpress.com/2012/09/21/uki...