I suppose the thing about UKIP is that it doesn't want to be a racist party, but the racists don't know that.
See, I'm not against concepts such as point-based immigration in certain cases etc, but I'm also pretty much pro-Europe in concept, though if it wants to become more politically centric instead of market-centric then I think I see a crisis coming with the way it manages itself, but I don't think that will be resolved by walking away from the deal.
The problem for me with UKIP was that Farage, whilst not someone who inspired confidence in me, at least gave the impression of trying to moderate the party, but whilst members were constantly rising into the public eye with racist comments, they could not break that association between UKIP and groups like the EDL and BNP.
I suspect like the other two groups, UKIP will, post election and sans Farage, slowly deflate like the other groups did. There is a warning in the rise of these Xenophobic aspects, but not really a threat to them.
I'm not saying Nationalist Parties cannot possibly get into power, look at Scotland, but you have to offer something that is unique, and the Conservatives took the wind clean out of UKIP's sails early in the election with offer of a Referendum, that's what it was all about so in a way UKIP achieved their main goal without even getting into Power.