Yesterday was Iain Duncan Smith's chance to stake his credentials as a potential Prime Minister. But is he the real thing? Political Editor Chris Lloyd reports.

AS one, the delegates rose from their chairs to greet Tony Blair. They clapped and cheered his appearance: his mannerisms, his beaming smile, his cheery voice saying "let it be done".

Only it was Iain Duncan Smith, leader of the Conservative Party, doing an impersonation of Mr Blair.

"Move over, Rory Bremner," said Mr Duncan Smith, the delighted look upon his face showing his surprise at the reception.

"But not just yet," he quickly added to quash any speculation that he was quitting politics for a job on television impersonating a politician.

It was, to be fair to Mr Duncan Smith, an extraordinarily good impersonation of Mr Blair. He did a far better job of sounding like the Labour Prime Minister than he did of looking like a genuine Conservative leader.

The delegates loyally gave him at least 19 'spontaneous' standing ovations, bobbing up and down so much that they looked like a knee operation aftercare clinic with all the patients flexing their new joints gratefully.

But a majority of them was only impersonating loyalty. According to a poll in yesterday's Daily Telegraph, 53 per cent of grassroots Tories think Mr Duncan Smith is a mistake as leader; 44 per cent want an immediate change; 71 per cent say that Mr Duncan Smith's frontbench is not an effective opposition, and 60 per cent don't think the party can win the next election.

And yet there they were, applauding away, the very personification of loyalty.

By common consent, the party was in open revolt on Wednesday. Former minister John Maples tried to summon up the 25 MPs needed to force a vote of confidence in Mr Duncan Smith. Fortunately, the England football camp was in even more disarray and Sven Goran Eriksson's "turkeys" prevented the Tories from getting a front page stuffing in the tabloids.

Yesterday in his speech, Mr Duncan Smith turned forcefully upon the plotters and told them in his meanest manner: "Get on board or get out of the way."

Last November, when his position was similarly imperilled, he turned on them then in his meanest manner and said: "Unite or die."

This, then, is a party that is impersonating progress because, as it claims to be moving forward, it is still fighting last year's battles. The party leader remains in office only because of last year's reasons: there is no obvious candidate to replace him, which means that any leadership contest would be brutal and divisive.

But even the party members are still fighting last century's battles. Interestingly, the loudest, longest and most sincere of the standing ovations came when Mr Duncan Smith spoke about standing up to Europe - if the members had really progressed, they would know that the European Constitution is important but, in today's climate, state schools and hospitals are even more important.

It is 13 years since Margaret Thatcher was brutally deposed as leader, but the Conservatives have yet to move on: still the same issues and the same strife sapping the party's energy.

This presents the public with a very difficult problem: if half of the Conservative Party does not believe in its leader, why should anyone outside the party believe in the Conservative leader's policies?

Particularly when they are presented so unconvincingly. Yesterday Mr Duncan Smith sounded as if he were just impersonating an orator. Unlike Tony Blair or William Hague, Mr Duncan Smith is not a natural on a stage - but someone has spent many months trying to teach him how to deliver a speech. He hadn't learned. His voice rose and fell unnaturally, his pauses were long and stilted, and his gestures puzzling. When talking about pensioners or children on drugs, he affected compassion by knitting his eyebrows tightly together. He lifted his nose as if a bad smell were troubling it, and made sympathetic sweeping movements as if he were playing a violin.

As an actor, Tony may well be phoney. But Duncan is bunkum.

Mr Duncan Smith wasn't helped by the nature of the stage: a dais placed in the round with no lectern for him to prop his woodenness against. The design would have been innovative and daring in other hands, but with Mr Duncan Smith shuffle-dancing uneasily around it, it only emphasised his vulnerability.

Yet Mr Duncan Smith would have got away with his presentational problems if he had had something fresh to say. In truth, he was a pale imitation of a man with an original thought in his head.

He said: "This Labour Government cannot hear them (the people) above the racket of its own spin and the rattle of its own demise." This may well be true, but his speech had been spun not just one but two days in advance. Mr Duncan Smith's spin doctors - who were orchestrating the standing ovations in the hall - had leaked it in a desperate bid to see off the plotters, but had left him with nothing new to say.

There were other inconsistencies, too. "The quiet man is here to stay and he's turning up the volume," he said, overlooking the incontrovertible fact that if a quiet man does turn up the volume he becomes a loud man.

And finally there was: "During the next election don't be surprised when Labour play dirty. A Prime Minister that lies about his own record won't hesitate to lie about us. A Government machine willing to smear the Paddington train crash survivors and Dr Kelly won't think twice about smearing me."

This, too, may well be true, but Mr Duncan Smith had opened his speech with a double-barrelled smear of his own: "We must destroy this double-dealing...deceitful...incompetent...shallow...inefficient...ineffective...corrupt...mendacious...fraudulent...shameful...lying Government...once and for all." His smear about Charles Kennedy - where he invited his party members to laugh at the LibDem leader's imagined drink problem - was distasteful, so how dare he not expect his opponents to fight dirty?

Aside from the stream of insults - designed to make Mr Duncan Smith look tough - there was a smattering of policy statements. The most interesting of which - like elected sheriffs to take control of local police - Mr Duncan Smith strangely didn't mention.

Instead, he concentrated on three new ideas plus one old one: 40,000 new police officers, restoring the pensions' link to earnings, and scrapping tuition fees. Plus cutting taxes. These are great vote-winners ideas - but only if they have substance behind them. The public isn't so stupid as to believe that it can pay less in tax but still get 40,000 more policemen.

Yesterday was Mr Duncan Smith's opportunity to explain his vision, but he didn't bother. Instead, he spent his time impersonating Arnold Schwarzenegger by being tough against the enemy within, the enemy without and the enemy across the channel.

It went down well in the hall; it might well have inspired die-hard Tories to fight hard against the dying of their party. It cannot have connected with the wider world.

Next week, when real politics resumes, the Tories will still be pretending to be united behind their leader while squabbling about the best way to replace him. And, as their grassroots members told the Telegraph yesterday, they will still be putting on a very poor impersonation of an opposition.