RARELY, if ever, has a government unravelled so quickly and so spectacularly before the electorate's eyes. Less than two weeks ago, Tony Blair was basking in the reassuring glow of anything up to a 15 point lead over the Conservatives in the opinion polls. The party conference season promised only nasty questions for William Hague for his failure to make any impact. Mr Blair was sailing serenely towards a second term.

Fewer than 14 days later, the Conservatives have anything up to a five point lead over Labour. All the questions are for Mr Blair. Their asking starts tomorrow, when the Labour Party conference begins in Brighton.

It promises to be the most important gathering since 1994 in Blackpool. That was Mr Blair's first as leader, and it was the defining moment when New Labour shook off the shackles of Old Labour. Although many in the Winter Gardens didn't realise as they applauded the new leader's speech, Mr Blair was scrapping Clause IV of the party's constitution - the bit about common ownership and nationalisation, the really socialist bit.

This coming week in Brighton promises to be equally defining. The Labour Party has never really loved Mr Blair. It has admired and respected him for what he has achieved, but the privately-educated Oxford University graduate who became a barrister has not been clutched to the working class soul as Michael Foot or Nye Bevan were. Now the rank and file must decide whether they like Mr Blair enough to close ranks behind him in his hour of need, or whether they are going to be like Cabinet minister Clare Short and kick him when he's too weak to respond.

Tomorrow presents a fascinating opening to the conference and an early test of loyalty to Mr Blair. Mo Mowlam, the most popular politician on the planet who has, by all accounts, been shabbily treated by her leader, is due to lead the first session with a speech on a "21st Century political party" and internal organisation issues.

In her first appearance since announcing she is stepping down from her Redcar seat at the next election, in what direction will this conference darling stray from her boring brief? Will she have a sly dig at Mr Blair or will she don a rah-rah skirt and do some tub-thumping on his behalf?

One North-East party member who was last night packing his bags for Brighton believes she will be at her morale-boosting best, and that will match the mood of the party.

'I think the rank and file have become a bit more protective of Tony Blair over the last couple of weeks,'' he said. ''It's a bit of a class war thing again. We've seen the farmers and lorry drivers blockading refineries. Many Labour members see them as people who have never liked us and never will."

This, though, presents Mr Blair with his age-old problem because farmers and small businessmen like hauliers are exactly the ones he wants to entice into his "big tent" politics. The people Old Labour is now reassured to see as familiar enemies are the very voters to whom Mr Blair has spent six years appealing.

At yesterday's Scottish National Party conference in Inverness, retiring leader Alex Salmond unwittingly explained how Mr Blair - once the most popular Prime Minister in modern history - has come to find himself in this situation. Mr Salmond said that most people did not follow the minutiae of politics or read the small print in the red book of a Budget. Instead they soak up the atmosphere and the mood music, and from that they form an opinion.

So a few months ago, as Mr Blair sailed serenely towards his second term, he was able to shake off the controversy over the Bernie Ecclestone donation. He was able to shrug off questions about the Millennium Dome. He was able to ignore the worries about a 75p rise in pensions.

Individually, none of those factors which now look so damaging had any effect on Labour's long-term poll rating. This is because the Opposition was too weak to exploit them, but also because the mood music was playing a different tune. Three months ago, for all the Dome's difficulties, Labour was throwing millions of pounds at the real structural problems in Britain. Health and education were getting massive injections and Labour was dominating the agenda. The small noises off about pensioner discontent were not being heard. They certainly did not require the drastic intervention that was seen this week when Gordon Brown made his pre-conference announcement about guaranteeing pensioners' minimum income.

Looking back on these times from today's perspective, Labour's ignoring of the pensioners' concerns and the squealings of the haulage industry look like an arrogant disregard, a complete failure to listen to the ordinary person.

That is because in the last 14 days, fuelled by the petrol protest that no one saw coming, the mood music has changed. The Dome is doomed. The Lottery has descended into farce. Mo was mugged. There's anarchy on the streets; the nation is held to ransom. The British people are pushed to extraordinary lengths because of an intransigent government.

Headlines shout of £1m lies. Ministers must resign. Pensioners are outraged. A court's decision about GM crops throws Government policy into disarray.

Even Mr Brown, the man who is widely regarded as the best Chancellor of the Exchequer for decades, the man who is the rock of New Labour, the man who is Mr Blair's successor, has found himself caught in the centre of the storm.

Whereas a year ago, Mr Brown's pension announcements would have been welcomed as the work of a deep-thinker - and, incidentally, they are thoroughly sensible in targeting the poorest - now they look like the actions of a man desperate to rehabilitate his own image and striving to stave off yet another ugly confrontation at the party conference.

Whereas just three months ago, the £4m given to prostate cancer research would have been a welcome addition to the billions being pumped into the NHS, in the last desperate fortnight it has looked pathetically paltry beside the £600m disappearing down the Dome.

And whereas only 14 days ago, Mr Blair would have headed for Brighton with a second term a certainty, this week he has to steady his ship for what is only a likelihood.

l Additional reporting: BRENDAN CARLIN

l Follow the Labour Party conference online at www.labour.org.u