Tory leader David Cameron said there was a "better than 50% chance" of an early election, as his party laid out tax-cutting proposals including a pledge to take the family home out of inheritance tax.
Shadow chancellor George Osborne said under a Conservative government estates worth less than £1 million would not be liable to the tax and also confirmed a promise to exempt from stamp duty houses for first time buyers sold for less than £250,000.
Mr Cameron, asked on Sky News whether there would be an election this year, replied: "I think the chances are better than 50%."
And he denied the tax proposals were a sop to party hard-liners, saying: "There's nothing lurching to the right about helping people with their aspirations."
His comments came after Mr Osborne cheered party activists at their annual conference in Blackpool with his tax promises. He said Conservatives wanted to help "people whose only crime in the eyes of the taxman is that instead of spending their savings on themselves they want to pass something on to their families".
He insisted: "The next Conservative government will raise the inheritance tax threshold to £1 million. That means we will take the family home out of inheritance tax."
The inheritance tax threshold is currently £300,000.
Mr Osborne said the two measures would be paid for by a flat-rate annual charge of £25,000 on those who register in the UK for non-domicile status to protect their earnings from income tax.
Chancellor Alistair Darling told BBC News 24: "Yet again, this is an example of where the Tories are making promises on tax which they can't afford to pay for."
Mr Darling said that 96% of estates currently pay no inheritance tax.
