After a strong showing in local elections so far, Nigel Farage has anticipated even better when the European results are published.
Asked whether the party was now a major force, Mr Farage said it feels like "the Ukip fox is in the Westminster henhouse".
UKIP's successes in the local elections have raised the possibility of them winning a Westminster seat at the general election.
A year ahead of the general election, Ed Miliband's party is seeing only patchy support in areas it should expect to gain ground.
UKIP are likely to make Rotherham a key target for 2015 after a storming result in the local elections.