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.
A Labour backbencher has slammed the party's "disastrous" electoral strategey and criticised Ed Miliband for not reaching out to a wider spread of voters.
John Mann told BBC Radio 4's World At One programme: "He's not broadening the appeal to take into account the views of people like me and other MPs and the views of our constituents.
"That isn't happening, that's why they didn't take on Ukip. Some of the pointy heads at the top of the party thought that Ukip doing well is what we needed."
The Bassetlaw MP added: "The people deciding strategy at the top, without question, had a strategy of ignoring Ukip instead of taking them on and that was a disastrous strategy."
The Conservatives passed 100 lost seats by lunchtime today, with Labour seeing a jump of 128 with 89 councils still to declare.
Ukip's surge roughly matched the losses suffered by the Liberal Democrats, as Nigel Farage's party gained 85 to the 88 lost by the coalition government's smaller partner.
Nigel Farage said Ukip's gains in the local elections "look like a fairly permanent protest" as he arrived to cheers in Thurrock this afternoon.
Mr Farage added it was difficult to predict whether his party's surge would be more harmful to Labour or the Conservatives, as many who voted Ukip "probably hadn't voted for anybody for 20 years."
Nigel Farage was mobbed by supporters as he visited Thurrock in Essex to celebrate his party's five seats on the local council.
Ukip's strong showing in the borough meant Labour lost their overall majority, and Farage's visit prompted further celebrations among local party members.
Speaking during the visit, Mr Farage said targeting marginal constituencies, like Thurrock, could be the key to success in next year's general elections.
David Cameron says his party's losses in the local polls show that "people want us to deliver" - adding that the party will not do a pact with Ukip ahead of next year's general election.
The Prime Minister said the Conservatives would be working "flat out" to deliver answers on issues that are "frustrating" people, like immigration and welfare.
Questioned on any potential pact with Ukip ahead of next year's vote, Mr Cameron said: "We are the Conservative Party: we don't do pacts and deals.
"We are fighting all out for an all out majority at the next election."
Liberal Democrat leader Nick Clegg has said he will not resign following big losses in the local elections so far.
The Deputy Prime Minister conceded that his party had suffered at the hands of a Ukip surge, blaming a "very strong anti-politics feeling" among the public.
But he added: "Actually I think in the areas where we have MPs where we have good organisation on the ground... we are actually doing well."
Labour leader Ed Miliband says voters are turning to Ukip as an expression of discontent that has building for "decades".
Speaking following large gains for Nigel Farage's party in the early election results, Mr Miliband said people were frustrated and felt "that the country just doesn't work for them".
"What you're seeing in some parts of the country is people turning to Ukip as an expression of that discontent and desire for change," he added.
"I believe we can persuade those people that Labour can offer answers to them and to the challenges they see in their own lives."