YouGov.

The UK Independence Party is on course to win this May’s elections to the European Parliament. YouGov’s first survey in the run-up to the election puts UKIP on 26%, six points behind Labour and three ahead of the Conservatives. In past euro-elections, UKIP’s support has increased as the election approaches. If this pattern is repeated, UKIP is likely to overtake Labour by polling day.
http://yougov.co.uk/news/2014/01/16/european-elections-ukip-closes-first-place/