In the past I would say that the prime difference between British politics and the sort practiced across the English channel was that the British political parties staked out clear, and clearly different, party platforms. On the continent things have typically been rather more nuanced and governments have tended to be formed of coalitions of parties who govern because they agree on some platform of stupifying blandness and where the official opposition presents a program that is almost completely identical except for a few tedious details in section 3, subsection 55, paragraph 2(a)xii.
Up until the last few (1-5 depending on how you count things) years the three main UK parties (Labour, Conservative and Liberal (Democrat) ) have at least been significantly different in policy platform and have not expected to govern in coalition. This no longer seems to be the case as the difference between Blairite ZANU Labour and the Cameroonian Nouveaux Conservatives has become almost non-existent and the Lib-Dims, in an attempt to get elected, have also ditched almost all their nuttier policies too. In other words we have a choice between ZANU labour red big government, Nouveau Conservative blue big governent or Lib Dim yellow big government with a super greenish tinge (and in the celtic fringes you also have big government with the celtic plaid of your choice). In other words all the major parties have done the European thing and triangulated themselves into bickering over tedious details in section 3, subsection 55, paragraph 2(a)xii.
As a result, I suggest, the electorate has become somewhat disillusioned. EURSOC reports that the Torygraph (and YouGov) have the results of an opinion poll that suggests that over a quarter of Britain feels that no major political party represents them. Furthermore the same poll points out that vast chnks of the electorate don't trust their politicians, don't like them and don't believe that being a professional politician is a good thing. This graphic from the Torygraph has all the sad details. This is remarkably similar to life in continental Europe over the last decade or so. In Europe this has resulted the rise of far right (and some far left or far green) parties who have moved slightly centrewards and reaped the electoral rewards. Five years ago in France recall that the Front National came second in the presidential race and the German far right is growing ever stronger, especially in the North and East. Somewhat less radically, Umberto Bossi's Lega Norda in Italy and the Vlaams BlokBelang in Belgium have combined regional policies with non-mainstream policies to good effect and the Netherlands was shocked by the popularity of the List Pim Fortuyn in 2002 as well.
Britain could well see something similar to this, since there are two or three "non mainstream" parties that could appeal to the dissaffected voters. UKIP (or whatever it renames itself as) is the one I hope will gain the majority of the disaffected but it is far from certain that the BNP will not also pick up a number of voters too.
In order to recuit as many votes as possible I believe that UKIP should promise, if elected in large enough numbers, to demand binding referenda on a number of contraversial issues, from membership of the EU, to capital punishment, hunting and state funding of the BBC. If the party were cunning it would also have in its manifesto that once the referenda had been chosen and laws modified (or not) based on them, it wold seek a second general election with a more detailed manifesto. Since all the major parties are pretty much bankrupt having two elections in close succession would be to the major advantage of the outsiders I think...