claig
I have enjoyed debating this topic with you.
I think UKIP's most likely success is to force the Tories quietly to the right. If history is any guide, they will need to get 30% in the election before they start picking up seats, as the Liberals/SDP demonstrated in 1983 and 1987. Any less, and all they will achieve is the defeat of Tory candidates in favour of Labour and Lib Dem candidates who, in all probability, will be more Europhile.
And I really don't think they will get 30% come an election or anything like it. Not if you consider what happened to the Lib Dems at the last election. As soon as the media spotlight was on them - seriously on them - their policies and senior politicians got scrutinised far more closely than before. The result? A heck of a lot of their policies weren't robust, and not enough of their top-rank politicians were robust enough to defend them. Because of this, and because of their maladroit, if not downright naive manoeuvres after the election, their vote will probably get cut in half - regardless of whether it turns out that the Coalition was right on the economy after all. Sure, the Lib Dem vote went up in 2010, but on polling day it was a fair bit down from halfway through the campaign when, according to some polls, the Lib Dems were actually out in front.
If this is what happens to a party that is pretty well seasoned, it'll be a bloodbath for UKIP unless they can poach a few senior Tories over to their side.