UKIP are riding a perfect storm

Since UKIP's success in the local elections the news has been a nice reminder that the next 12 months are going to be filled with various Tory backbenchers offering unsolicited advice on how David Cameron can win back the UKIP vote.

But first it would be useful to know where that vote comes from and I'd say it's caused by four factors:

1. The Tories are in government and true-blue, old school conservatives need somewhere to go. This is partly down to the steps David Cameron and other modernisers took to detoxify the party after the 2005 election defeat but the thing it most resembles is the desertion of left wing voters from Labour to the Liberal Democrats around the time of the Iraq war. Not to diminish opposition to the war but there is a pattern of a party entering government, making decisions and compromises and naturally failing to live up to the hopes of core supporters. By 2005 the Lib Dems were running to the left of Labour in many areas and where UKIP has clear policies they tend to be tax cuts, increased defence spending and opposition to gay marriage, precisely the sort of thing traditional conservatives want and which David Cameron can't give them.

2. As everyone has noted, the Lib Dems are in government as well which robs them of their traditional protest for support. Labour are still not particularly trusted as it was only a few years ago that they were the thing people protested against so that sentiment has to go somewhere. Not to diminish Alex Salmond's achievements but this no doubt benefited the SNP in 2011 and is fueling UKIP now. It's also the reason why UKIP are drawing support from across the political spectrum. Why would anyone switch from the Lib Dems to UKIP based on policy without a serious shift in their beliefs.

3. There has been a general tend over the last 40-50 years away from two party politics. In 1955 the combined Labour/Conservative share of the vote was 96%. In 1970 it was 89% before dropping to 75% in 1974, rising briefly to 81% in 1979 and by 2010 it was down to 65%. There are lots of explanations for this and I won't go into them here (though I do recommend Denver, Carman & Johns on alignment and dealignment) but it is a fairly established trend and this is the most recent manifestation of it.

4. Finally we come to Europe. If the UK's membership of the EU was really the driving force behind UKIP then surely there would have been a polling bounce for David Cameron and the Conservatives after the PM promised an in/out referendum if elected in 2015. Just before he made the speech UKIP were on 14% in the Opinium/Observer poll and in the next one they were also on 14%. The Tories went from 28% to 29% so hardly a game-changing surge. EU membership is more an obsession of the political class than the public and while people tend to express sceptical opinions when asked, the Ipsos MORI/Economist tracking poll shows they rarely assign much importance to it. However, as I've mentioned before, the constant stream of apocalyptic news coming from the eurozone has likely had some effect. Despite very vocal hostility among its MP's and members, the Conservative party is still officially in favour of EU membership, as are Labour and the Lib Dems, leaving UKIP as the only prominent party officially in favour of 'brexit'. This is as potent an issue as any to differentiate yourself from the political class and Nigel Farage has recently made the obvious but still shrewd connection between EU membership and immigration from EU countries, an issue which the public really do think is important.

UKIP are now probably favorites to win the European Parliament elections next year (although I think Labour still have a chance) and when that happens the abuse David Cameron had been getting from right wingers up until now will seem fairly timid in comparison.

The key thing, that nobody can really say with any certainty, is what those voters will do when the election is about choosing the next prime minister rather than councillor. UKIP came second in the 2009 European Parliament elections with 16.5% of the vote but in the general election a year later they only managed 3.1%.

David Cameron will be hoping that this precedent repeats itself in 2015 and that still seems likely. But remember: UKIP never used to win council seats either.