The United Kingdom Independence party will trigger a political "earthquake" in next year's European parliamentary elections, its leader, Nigel Farage, has said.

Amid growing calls from Tory MPs for David Cameron to respond to the Ukip threat by bringing forward legislation on an EU referendum, Farage warned that his party would not go away even if No 10 "starts singing the same song".

William Hague, who famously suffered a major defeat in the 2001 election after tacking to the right, called for a cautious response to Ukip as he warned of the dangers of "quick fixes".

Philip Hammond, the defence secretary, said many Ukip voters were "frustrated Conservatives".

As the Tories work out their response to Ukip, which won nearly a quarter of the vote in wards it contested in the local elections, Farage said he would not be standing in any byelection over the next year as he focuses on the European parliamentary elections.

The Ukip leader told The Andrew Marr Show on BBC1: "Ukip is here to stay … June 2014 we have a European election. That is the day on which Ukip can cause an earthquake in British politics. I want to lead the party into that."

Asked whether he would stand for parliament in the 2015 general election – he stood against the Commons Speaker, John Bercow, in Buckingham in 2010 - Farage said: "Yes I will stand for a seat in 2015. I have been rather busy for the last few weeks doing other things [to decide which seat to contest]. But I will think about it."

Farage pointed out that Ukip was picking up votes not just from the Tories, saying his party won 24% of the vote in the South Shields byelection, mostly from old Labour supporters. He added: "Please don't think that Ukip is just some little pressure group that will go away because somebody in Downing Street starts singing the same song."

The Ukip leader, who has said he will refuse to negotiate with Cameron after the Tory leader called his party "fruitcakes", said he would be open to holding discussions with another Tory leader though he said this was not his priority.

"If David Cameron gets removed … and somebody else was put in place who wanted to come and talk to us and say, 'Shall we find an accommodation?' we would consider it.

"But it is not my priority. My priority is to build a new political party, a movement in this country that actually wants to stand up for the interests of ordinary people."

Hammond acknowledged that Ukip presented a threat to the Tories but said it would be difficult for the government to bring forward legislation for an EU referendum in this parliament in the face of Lib Dem opposition.

He told The Andrew Marr Show: "The great majority of the people who supported Ukip are ordinary decent people. Many of them are frustrated Conservatives – frustrated at the length of time it is taking to get the economy growing again, frustrated about the constraints of coalition government, frustrated about the way globalisation limits our ability to control the world that effects.

"We understand that is people's concerns and we are addressing the key issues they care about. Immigration down by a third, deficit down by a third, welfare capped."

Hammond said it was important to point out that the Tories are constrained by coalition government as he said it would be difficult to introduce legislation on an EU referendum during this parliament.

"I understand people's scepticism; they are saying: 'Yeah yeah, that is the other side of an election … What can you do now to reassure us?'" the defence secretary said.

"We should do everything we can to reassure people about our commitment [to hold a referendum in the next parliament.] We should make it in very clear and unambiguous terms including publishing a draft bill. The simple reality is we would not get a bill through parliament in this parliament."

Hague said it would be wrong for the Tories to embark on a shift to the right as he rejected "quick fixes".

In an article for the Sunday Telegraph, the foreign secretary wrote: "There is always a temptation for politicians to offer quick fixes; to say we can cut taxes, increase spending, bring down the deficit and solve our problems with a magic wand. When times are hard the temptation to do this is even stronger. People are tired of bad news.

"Many want to hear that there's a Plan B or C or D that is a shortcut to success. But to offer shortcuts that will not work would be to cheat the British people, offering them a dead end – and frankly it is patronising to them too."