UKIP’s goal is success in getting elected to the EU parliament, which is an odd goal to have in a way — but could make them the cork in the dam.
The only thing that could really disrupt the EU (aside from a UKIP-type majority voting “no” to every Commission diktat) is a similar-minded person being appointed as a commissioner and circumventing his oath to go against his home land and being for the EU in all things.