DAVID CAMERON this weekend challenged Gordon Brown to “stop dithering” and call a general election as the Tory leader unveiled radical tax-cut plans ahead of a make-or-break party conference in Blackpool.

With some ministers now claiming there is an 80% chance of Brown calling a poll for early November, Cameron says in an interview with The Sunday Times that he is “very excited” by the prospect and “really up for it”.

“He should stop dithering,” Cameron said. “He’s got himself into a position where he either bottles it or he has given us a hell of a lot of notice of his intentions. We’ve had lots of time to hunker down and plan the election, which has been good. The machine is really ready for an election.”

The Tory leader said that despite double-figure opinion poll leads for Labour this weekend, any contest would be “wide open” because most voters “have not made up their minds”.

An Ipso-Mori poll for The Observer today gives Labour a seven-point lead on 41%, against 34% for the Tories and 16% for the Liberal Democrats. Only 13% thought Cameron was the best leader to handle a crisis, compared with 60% for Brown.

Even some members of Brown’s inner circle acknowledge that the prime minister could look weak if, after allowing the prospect of an autumn poll to be raised, he were now to announce that he will not call an election this year.

“Gordon will need to move swiftly on ruling in or ruling out a poll,” said a government aide. “He is going to have to make an announcement either way, because to let this dribble on without making clear his intentions could lead to the charge being made that he is indecisive.”

In his interview, Cameron acknowledges commentators have a “fair point” in highlighting the confusion over lack of clear policies. However, declaring that he is ready for a “very big fightback,” he today announces a tax cut worth £2,000 for first-time buyers to help them get a foot on the housing ladder.

The Conservatives will go into the election with a manifesto promising to abolish stamp duty for first-time buyers on homes worth up to £250,000. The party claims that this will mean nine out of 10 would-be home owners will not pay the levy, saving an average of £2,000 for about 285,000 people.

The move by the Tory leader, which will please the traditional wing of the party, will also appeal to the “lost generation” of prospective homeowners, frozen out by the steep house price rises in recent years.

Cameron said the tax break was an example of a key theme of this week’s Tory conference: “giving people more opportunity, power and control over their lives”. He said: “It’s a classic example of the Conservative party being a party of aspiration, giving you power and control over your life.”

Aides say the move is just one of a package of tax measures to be announced. George Osborne, the shadow chancellor, is considering plans to raise the current £300,000 threshold for inheritance tax - which is already due to rise to £350,000 by 2010 - and to reduce the 40% rate at which the tax is levied. He has also appeared sympathetic to the proposals to axe the tax on a main residence.

Cameron this weekend outlined plans to hand families tax breaks, designed to end the benefits “anomaly” that the Tories claim punishes parents for staying together. About 1.8m families who are raising children would be up to £2,000 a year better off, according to the party. The £3 billion measures would be funded with a crackdown on “workshy” benefits claimants, including “aggressive” penalties for those who turn down jobs.

The Tory leader arrived in Blackpool yesterday aware, however, that he has a huge task ahead of him, with two opinion polls this weekend giving Brown a 10% and 11% lead over the Tories and with critics of his “modernising” agenda waiting in the wings.

The most likely dates for the general election are now November 1 or 8, after a poll in late October was ruled out because it would clash with the school half-term holidays. Brown’s aides are conscious, however, that asking people to go out and vote when the nights are drawing in could backfire on Labour. They fear their support could be disproportionately affected by swathes of the electorate staying at home.

A further sign of an impending poll came last Friday when Jacqui Smith, the home secretary, told her civil servants as they left the office that the government “might be in purdah next week”, referring to the period ahead of an election where ministers are forbidden from making spending announcements. Some Labour MPs are cancelling their engagements for next week and returning to their constituencies.

While the Brown cabinet was last week split between “young turks” calling for an early election and more experienced members expressing caution, the official line from Downing Street is that the prospect of a November poll is still “in the balance”.

As well as being wary of going to the polls during the darker autumn days, Brown aides will be aware of research that suggests the national opinion polls giving Labour a big advantage could be misleading.

Professor Colin Rallings, director of Plymouth University’s elections centre, pointed out that in 35 council by-elections since Brown took over as prime minister, the Tories have a nine-point lead over Labour.

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