New UKIP Votes.

There are possibly millions of, as yet, 'unclaimed' UKIP votes which are yet to manifest themselves. In the council elections, there are many hundreds of seats where UKIP has taken a good second place or a third in a narrow, three way split.
Voters in those areas now all recognise that UKIP can win next time. Many of those votes will start to show themselves in the next council elections.