Yesterday, in Birmingham's impressive Symphony Hall, it was not only the venue and the opinion polls that had changed. The Tories may have enjoyed a year in the political ascendancy, but 12 months of economic turmoil culminating in the near- meltdown of the global financial system have left voters to make a decision over whether to stick with experience or opt for change.

Mr Cameron yesterday made his case for change, to give the "man with a plan" a chance. It went down well with the faithful, but the big question now is whether it penetrated beyond the conference hall?

As far as party conferences go, the atmosphere in Birmingham has been strange. When banks are collapsing, stock markets are tumbling and doom-mongers talk of the collapse of capitalism, the story has really been elsewhere.

There wasn't any need to issue warnings against signs of triumphalism about recent successes that could play into the hands of Labour – a quick glance at the latest developments on the TV screens dotted around the exhibition halls was enough to calm the atmosphere.

But in a strange way, the financial emergencies of this week have given Mr Cameron and his Shadow Cabinet the very chance they craved – to challenge the Prime Minister's claims that they could not be trusted. And not just with words, but through action as well.

Twice – on Sunday and Tuesday – the Tory leader could portray himself as a sombre statesman making unscheduled addresses to the conference to explain how he would guide the country through difficult times. Even his address yesterday was given from behind a statesman-like lectern instead of the free-roaming performances with which we have become accustomed. He has gained the moral high ground by offering to set aside party differences in the national interest. And sending George Osborne to the Treasury for talks with the Chancellor also played up to the image of a government-in-waiting.

At times in recent months, the Tories have appeared weak when challenged to show how they would deal with the economic crisis. While they have by no means answered all the questions asked of them, we do now have ideas set out in writing which better articulate why they continue – against the public mood – to oppose extra regulation. They have been able to appear on the front foot in offering to support emergency legislation allowing the Bank of England to rescue failing banks and in calling for protection for savers to be increased from £35,000 to £50,000. The party has also appeared more in tune with public anger directed towards the bankers who were allowed to get away with reckless borrowing, insisting there will be a "day of reckoning" once the crisis is over.

But if staking a claim to have credible economic solutions was the main challenge for the Tories over the first days of their conference, the test for Mr Cameron in yesterday's set piece speech was to convince the masses of undecided voters that this is a leader with both style and substance and that the Tory party of today is no longer the "nasty" party many of them fear.

He took on the doubters. Whereas Gordon Brown's weak position forced the Prime Minister to use his speech to plead with party members to stick by him, Mr Cameron's strength meant he had no need to pander to the faithful and could instead set out a bold vision for Britain, leading a reformed party ready to stamp on Labour territory such as the NHS, social justice and welfare reform. Yes, he wanted tax cuts, but not at the expense of financial stability
so there were no rash promises simply to please some of the die-hards.

For those who question what the man himself stands for, we were given a clear outline – a government based on strong defence, the rule of law and sound money, led by a "child of my time" who is determined to do what is right not just what is popular. He believes the role of the state should be slimmed down but is by no means "laissez faire". He equated his desire for change
now to Margaret Thatcher's defeat of James Callaghan in 1979, pleasing the die-hards, but
also drew clear dividing lines with her both by resisting pleas for tax cuts and insisting the Tories are now the ones who believe in society.

Some will mock Mr Cameron for speaking about social justice and mending society at the same time as talking about a smaller state and reduced public spending, but his demand for the Government to tighten its belt at the same time as families tighten theirs will resonate.

The dividing lines are now clear: Labour's continued spending versus the Tories who will review every spending programme.

As a speech, it may have lacked some of the fire to make it truly memorable, but you can't pledge to set aside party politics and then throw the kitchen sink at your political rival.

So the Tories will regard this week as a success. The reality, however, is that with an election still up to 18 months away, many voters will not yet make their choice. And while a conference speech can take on the mantle of being high stakes to all of us living in the political bubble, in the current climate especially, its resonance much beyond that may be limited.

If the Tories do go on to win the next election, the past few days are likely to go down as having been a stepping stone rather than a defining moment.

Jonathan Reed is the Yorkshire Post's political editor.