By Mark Davies BBC News Online political reporter

When Labour was trying to recast itself as a viable alternative to the Tories, they threw red roses to their followers.

The Conservatives came up with a different tactic as their spring conference in Harrogate came to a close on Sunday - they allowed a crowd of youths to storm the stage.

How things change. Harrogate, sedate Harrogate, the spa town famed for its tea rooms, now has a lap-dancing club.

Perhaps they'll give us a free skateboard

Conference delegate

And at the Conservative conference, there was a party leader surrounded by smiling young faces in tracksuits, leather jackets and jeans clapping their hero.

Who says the Tories are the party of the blue rinse set?

"Perhaps they'll give us a free skateboard," murmured one delegate afterwards as he reflected on this display of youthful vigour.

It was, of course, an obvious tactic. The vast bulk of the audience may have been of a more traditional Tory bent, but under Iain Duncan Smith the party has acknowledged that it needs to attract supporters from across the social spectrum, including these young folk.

Mr Duncan Smith's speech had been well trailed and offered few extra surprises. He strode onto the stage amid a fanfare and a flurry of flashing lights, but brought his audience down to earth with a bump.

He recalled his experience on the Easterhouse estate in Glasgow and the drug abuse, graffiti and general decay he had come across.

Three-quarters full

There was a "moral challenge" to help people in such areas, he said. This is the voice of modern Conservatism, the party which says it wants to help the most vulnerable people in society and which isn't obsessed by big business and wealth creation.

Tory aides don't like to call it a relaunch, but that's exactly what it was

That was the message for the outside world, at least. For those inside the three-quarters full auditorium, there was a different appeal.

It was time, he said, for the party to find different ways of presenting itself and its policies.

The Tories could not rely on winning power because of Labour's failures, he said, but by persuading voters that their party presented a better alternative.

That would not be achieved by "shouting louder" about Labour's errors, but by transforming the way the Conservatives conduct themselves: a new approach to politics.

After all, everyone laughs at cranky old pensioner Victor Meldrew shouting on television, he said, but no-one would vote for him, would they?

'Popular prejudices'

Mr Duncan Smith paid tribute to Baroness Thatcher, but it was also significant that he called up the experience of George W Bush in the US as inspiration for his party.

Mr Duncan Smith got a standing ovation for his speech

He was elected, he said, because Americans trusted him to deliver change because they admired his principles.

But he admitted there were "popular prejudices" about the Conservatives which the party needed to address.

Candidates should be selected regardless of their age, sex or background, he said. That would no doubt have down well with the young supporters who trooped up on to the stage at the end.

The speech was one of Mr Duncan Smith's better efforts, though as one observer put it: "It's all relative."

World outside

But as a delegates filed out, there was a general air of approval. "Well delivered," said one. "Balanced and focused," said another.

Of course, they were not the most important audience for the Tory leader. It is the people outside who really matter.

Which is why Mr Duncan Smith's speech in particular has been described as a relaunch of the party this weekend in Harrogate.

There have been other significant moments as well: Michael Howard, the shadow chancellor, intimated that tax cutting might not be an option if public services are to be improved, for instance.

But the leader's speech went to the heart of things. Tory aides don't like to call it a relaunch, but that's exactly what it was.

Mr Duncan Smith's first few months as Tory leader were understandably overshadowed by the events of 11 September last year.

His team say he is not saying anything now that he wasn't saying back then.

Murmurs of approval

But what he has certainly done, whether it was back then or now, is change the emphasis, to try to reach out beyond traditional Conservative supporters and to evoke his party's one nation roots.

There is an acknowledgement that the party in the past has appeared to only care about money and tax cuts, that their social reform message has been blurred.

The party leadership are careful to say that they are not taking the votes of core supporters for granted.

But at Harrogate this weekend they have reached beyond the people who murmured with approval in the conference hall.

It may not be a revolution in Tory thinking, but it at least represents a significant moment in its recent history.