By Lord Ashcroft

Tomorrow night’s European Parliament election results will bring a frenzy of analysis and speculation. Why did so many people vote UKIP? Who did they support before? What do they care about? And most of all, what will they do when it comes to the next election?

As we pollsters say: you can guess, or you can find out. In the 12 hours after the polls closed on Thursday night I surveyed over 4,000 people who took part in the Euro election. My poll doesn’t try to predict the result – that would be illegal before voting has finished in all European countries – but it helps explain why voters did what they did, and what they might do next.

Eight in ten of those who voted UKIP said the party had the best policies on Europe – but six in ten also said they were sending a message that they were unhappy with the party they usually support, or making a general protest. But at the next election, their votes are up for grabs – especially for the Tories.

Two thirds of Thursday’s UKIP voters think David Cameron is the best available PM, compared to a quarter for Ed Miliband. And nearly seven in ten trust Cameron and Osborne more than Miliband and Balls when it comes to running the economy. (Indeed one in ten Labour voters trust the Tory duo more than their own two Eds). Just over half of UKIP Euro voters supported the Tories at the 2010 election. One in seven voted Labour, and a fifth were Lib Dems. As for next May, only half of them expect to stay with UKIP.

One fifth already say they will go back to the Tories, one in ten will vote Labour, and 14% say they don’t know what they will do. When it comes to the general election, the economy will dominate. And while immigration is also high on the list, it is neck-and-neck with the NHS – a useful reminder to all parties not to let last week’s issues dominate the debate for the next year.