UKIP is here to stay, says Nigel Farage
The UK Independence Party is "fundamentally changing British politics" with its goal of "getting our country back", Nigel Farage has said.
The UKIP leader said the party was "here to stay" and offered a change from existing parties which were almost "merged" in terms of their policies.
There have been Tory calls to change course to win back voters who switched to UKIP in England's local elections.
But Mr Farage said UKIP took votes from Labour and Lib Dems, not just Tories.
"We are the party with the broadest appeal across the country: north, south, east and west, old Labour voters, rural Tory voters, we are a genuinely national political party," he told BBC One's Andrew Marr Show.
"Now, to succeed in Westminster in 2015 we've got to grow and build a lot from here - but please don't think that it's impossible and I promise you this, UKIP is here to stay."
The UK Independence Party, whose main policy is for the UK to leave the European Union, gained about 25% of votes in the council seats it contested in England's local elections on Thursday.
Mr Farage said that the party's rise to having 147 local councillors gave the party a "bridgehead" to show what it can do.
There have been calls for the Conservatives to harden their commitment to a referendum on UK membership of the EU.
Conservative cabinet minister Philip Hammond said he hoped there would be a draft bill on a referendum ahead of the next general election.
Former Tory chairman Lord Tebbit also called for a date to be set for the referendum David Cameron has promised if the party wins the next election.
Mr Farage was asked whether a Conservative referendum pledge - and other policy changes - could lead to a deal being done between the two parties.
He said: "They're talking about it, but they don't mean it - and everyone knows that.
"You know, Mr Cameron set the course of this coalition government, indeed his own leadership since 2005 has been pro-EU, pro-open door immigration and pro-building wind turbines all over our green and pleasant land.
"He's not going to U-turn on all of those things, if he does, well, good luck to him. But please don't think that UKIP is just some little pressure group that will go away because someone in Downing Street starts singing the same song."
Foreign Secretary William Hague said that, from his experience campaigning for the local elections, people wanted a government which was doing the things currently being done - tackling the deficit, cutting immigration and capping welfare.
He said the government had to make sure that message was put across clearly.
He added, on Sky News' Murnaghan programme, that voting in the general election would not be "an indulgence" as it was for some voters in local elections - it would be a choice of who was going to run the country.
UKIP was the current "vehicle for the protest vote", as a variety of parties had been over the past 30 years, he said.
Deputy Lib Dem leader Simon Hughes said the Lib Dems had to take UKIP seriously and that the coalition was taking action on issues such as immigration.
But Mr Hughes said his party had done better in the local elections than in the previous two years and that they would continue to make the case that UK membership of the European Union was a "net plus for Britain", and also push the positives of immigration.