Until a few years ago UKIP was a single issue party. The only policy was to leave the EU.
UKIP stills wants to leave the EU.
It all boils down to the question of 'what is a country'.
Some of the things that any country should be able to do are:
Set its own tax rate
Control its own borders in terms of who it admits and who it refuses entry to
Should be able to defend itself
Should be able to make its own laws
etc, etc etc
Many of those things we are no longer able to control as we have lost the sovereignty over these issues when we derogated powers to the EU.
So, we no longer fully control our own borders as we must admit any person who is a citizen of a fellow EU country. That's why there's this fuss over the entitlement of additional Eastern Europeans to come and live here from 2013.
We no longer make all our laws as we have to accept that EU law takes precedence over UK law unless we explicitly opt out of specific EU Regulations.
So, according to UKIP the criteria that underpin the ability to call yourself a self-determining country are being dismissed or removed by our membership of the EU and the only way to recover that sovereignty is to leave the EU.
The UK pays £53million pounds a day for EU membership. The waste within the EU is depressing as it has vast armies of bureaucrats on huge salaries at a time when Cameron is drastically reducing the UK Civil Service in terms of numbers and conditions. The EU has also failed its audit for several years - so there are questions about where the money has actually gone. It's wasteful in having to up sticks and move between Brussels and Strassbourg every year which wastes millions in terms of manpower, transport and disruption.
UKIP also dislikes the fact that many of these EU officials are not elected. They are appointed by their Govts (e.g. Kinnock, Chris Patten, Peter Mandleson etc). That means you and I have no say in their appointment and cannot vote to remove them - a democratic deficit according to Tony Benn's test of:
What power have you got? Where did you get it from? In whose interests do you use it? To whom are you accountable? How do we get rid of you?
Cameron seems to think we can negotiate with the EU to cover that lost sovereignty and still remain in the EU. But he's running out of time for negotiations before the next election in 2015 and any referendum on any revised membership terms would have to take place post 2015 by which time the Tories will probably have lost power.
UKIP has now expanded its manifest from the single issue of leaving the EU to encompass a whole host of traditional Conservative ideals (grammar schools etc) in order to appeal to a wider audience.