The Conservatives will reveal a host of new policies today in a last-ditch attempt to unite the party and dissuade Gordon Brown from calling an autumn election.

With polls over the weekend showing Labour with a double-digit lead and the prospect of an election this year casting a dark shadow over the Tory conference in Blackpool, shadow ministers are desperate to claw back the electorate’s support. On the second day of the gathering, George Osborne, the Shadow Chancellor, will announce several eye-catching tax initiatives and a pensions compensation fund. He is expected to announce a reduction in inheritance tax to be funded by toughening the treatment of non-domiciled millionaires, who have been criticised for taking advantage of tax loopholes.

Plans to bring risk back into childhood by making it harder to sue schools and voluntary groups will also be outlined.

The moves are part of what David Cameron hailed yesterday as “the great Conservative fightback”. He told party activists: “It is going to be a fightback based on clear policies, based on a clear direction and based on the clear choice that we will give people at the next general election: more failure from Labour, more real change from the Conservative Party.”

Throughout the day he and other senior figures threw down a challenge to the Prime Minister to call an autumn election. But behind the bravado the mood was grim, and the challenge was more an attempt to sow doubt in Mr Brown’s mind about going to the polls early than a display of true confidence.

The Prime Minister met close colleagues this weekend to consider the latest polling information and reports from the marginals. A more formal “council of war” of key election strategists will be held in the middle of this week, but there will be no announcement on an election decision while the Conservatives are meeting.

Tory efforts to dissuade him from calling an early election were given an unexpected boost when John Turner, chief executive of the Association of Electoral Administrators, said that to do so could disenfranchise more than a million people and create chaos in the system of postal voting. Recent changes in the law designed to tackle identity fraud meant that all postal ballots had to have special “identifiers” for computer checks. That caused serious difficulties during May’s local elections, and the problems would be “multiplied several times over” in a general election because turnout was higher. Labour sources said that Mr Turner had raised an issue of which election planners were aware and it would be taken into account.

Mr Cameron was given a reminder of tensions beneath the surface when a Tory MP touted as a possible defector to Labour warned him against shifting the party to the right. John Bercow — who embarrassed the leadership last month by agreeing to advise Mr Brown on children’s learning difficulties — said that returning to the “comfort zone” of traditionalists would end in electoral disaster.

He praised the modernising approach Mr Cameron adopted after taking over nearly two years ago and urged him to go further to win the political centre ground.

David Willetts, the Shadow Universities Secretary, will say today that the “compensation culture” has damaged the quality of children’s lives and deterred teachers and others from offering challenging experiences to children. Under Tory proposals those organising sport and outdoor activities for children would only be successfully sued if they had shown a “reckless disregard” of the risks.

“Children need play, adventure and excitement. But the fear of litigation means school trips and adventures are now abandoned,” he will say. “Instead children get their excitement by retreating to their bedooms to play video games or the artificial stimulus of drink and drugs.”

Michael Gove, the Shadow Schools Secretary, will also outline proposals today to create more “pioneer schools” — independent, state-funded schools that can be set up by charities, commuity groups and other not for profit bodies.

The promise of a pension lifeboat scheme will come from Chris Grayling, the Shadow Work and Pensions Secretary. The idea is to compensate pensioners who have lost funds since 1997, and to begin payments within three months of taking office.

Mr Cameron led the calls for an election. Asked on BBC 1’s Andrew Marr show if the Prime Minister needed to seek a mandate after replacing Tony Blair, Mr Cameron replied: “Yes, I think he does.”

The Tory leader said that one of the key aims of the conference would be to provide voters with clarity over exactly what policies his party would offer. His series of policy reviews had been “very successful” but it was time to set out clearly which would be adopted and which junked.

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