Oliver Letwin has rounded on critics who accuse the Tory leadership of lacking substance and dragging its feet over setting out a programme for government.
The party's policy director insisted it was working through its plans in "awesome detail" and would not be bounced into making premature announcements.
He told The Independent's fringe meeting, entitled Have the Conservatives Changed Enough?, that the party was "on the way", but still had a great deal of work ahead of it. Mr Letwin dismissed critics demanding immediate policy statements, arguing that they fell into two categories.
"They are our opponents who would love us to make the mistake again of wasting our time in opposition by announcing early policies that haven't been sufficiently considered rather than announcing later, in time for an election, policies that have been considered.
"Or they are journalists who are anxious for something they can write about."
He said: "I'm terribly sorry if we can't give you overnight a series of policies that you can dismember limb by limb ... That is not our plan." Mr Letwin, who said the leadership had a timetable and a vision and was sticking to it, rebuffed accusations that under David Cameron the party was simply engaged in a rebranding exercise.
"Modernisation is not about appearances, it is about realities ... it's about what we're actually like and what we will be actually like as a government."
Mr Letwin admitted the party still had an "enormous amount of work" ahead of it to communicate to the electorate its vision of "social responsibility", under which local communities and voluntary organisations take the lead in boosting public services and fighting poverty.
He argued that the party had to adopt the right policies rather than those that simply appealed to one section of voters.
"We are trying to form the next government, we are trying to persuade the British electorate to vote for us to form that government. We can't do either of those things successfully except by adopting the policies and the strategies and the vision we believe is right for this country."
John Bercow, a former shadow cabinet minister, praised Mr Cameron for stopping talk about Europe, immigration and taxation. He told the meeting: "We need more reform, more modernisation, not less, more 'Cameronism', not less, more appeals to the centre ground of British politics, not less.
"We've got the best chance in a generation to win again. Let's take it - let's not throw it away."
Tim Montgomerie, a former senior Tory official who now edits the ConservativeHome.com website, said some traditional supporters were feeling neglected in the new-look party and warned: "You only have to lose a few of these people at the edge to lose a parliamentary majority at the next election."Reuse content