The rise of Ukip has been partly enabled by a harmonisation of the main three parties towards 'the centre ground' (ie: where the median voter ideologically resides); by the growing sense of disaffectedness towards those three parties (expenses scandal, hacking scandal, various money and/or sex scandals); and by the Eurozone crisis which has undermined a core element of the economic argument for Britain's membership of the EU.
Normally, when the disaffected voter wanted to protest s/he would vote for the Liberal Democrats. This protest vote would show the Tories and Labour Party that their performance was 'unacceptable'. However with the Liberal Democrats in government they can no longer be used in that manner. Thus, in concert with the sense of disenchantment with politicians, the highly contentious UKIP party has become the new party of protest.
Ukip's opposition to the EU is based on the idea of British exceptionalism and sense of cultural difference. Britain's history, sovereign institutions, patriotism, and a sense of romanticised identity has created 'an ideal' which UKIP argues can be celebrated and restored to greatness only if the UK withdraws from the EU. This idea is problematic because that ideal is a shared memory of a few who view this idea of Britishness as the only ideal. There was of course no golden age, but for UKIP independence will bring about a restoration that can reaffirm Britain's greatness. Put simply, chasing a memory which never existed has become the key selling point of the party.
It is a simplistic message that is proving effective because the other parties are offering little but reality. Granted, how that reality is ideologically taken forward is a matter of debate (Labour, Tory, Liberal) however this does not resonate with the electorate because the perception of embedded corruption is so great as to render the distinctive character inert. Everyone is tarred by the expenses scandal, everyone seen as corruptly involved in some financial or sexual scandal, or are in the pocket of media barons. This image has created fertile ground for UKIP to challenge 'the establishment'.
It should also be noted that although UKIP opposes the establishment they are themselves textured by leaders who are very much part of that same establishment. Granted, they capitalise upon their difference but this is an artificially constructed image that is needed to distinguish themselves from the negative image of the establishment that has been created. This allows the party to portray themselves as anti-establishment despite their ideological beliefs. Indeed, Ukip's Thatcherite economic agenda and traditional moral values call for the restoration of a Victorian economic and social model that is very much part of how the traditional establishment was built vis-à-vis hard work and deference to authority.
Should the traditional view of the establishment be adopted then it would represent a strengthening of traditional individualism which would deconstruct the social and economic changes of the 20th Century. The abolition of the minimum wage, cutting spending on and privatising the NHS, abolishing the working time directive, much harsher sanctions for benefit claimants, reversing socially progressive steps in relation to homosexuality, a free market in education, nepotism and patronage as standard practice, and closing the door on the poor to aspire. And yet it is those who benefit from these progresses who are gravitating towards voting UKIP.
Also the power of Ukip on the mainstream is not electoral. They will never form a government with over 326 Westminster MPs. But they can affect the policy agenda of the mainstream who are rattled by this success. The Conservatives are offering a referendum on Europe because they are scared of Ukip. The Labour Party is concerned about immigration because they too are scared of Ukip. It is this effect where Ukip can affect the political and social agenda.
The solution to this issue is to put a positive case for the mainstream by reaffirming confidence in themselves. One does not defeat the enemy by becoming the enemy. Rather by showing them and the broader electorate why they believe in ideas of tolerance and democracy can Ukip's tide by turned.