Nigel Farage has hailed his party's success in the local elections, saying it had put the "Ukip fox in the Westminster henhouse".
UKIP gained more than 150 English council seats, as the Conservatives and Liberal Democrats suffered big losses.
Labour took the most seats, but Ukip also ate into their support to add pressure on leader Ed Miliband.
ITV News Political Editor Tom Bradby reports.
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.