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After two years, the Cabinet finally admits that new Labour can seriously damage Tory prospects

The Cabinet yesterday abolished the past by settling on the slogan "New Labour, New Danger". At its political meeting yesterday, it finally buried the option of arguing that Tony Blair has not really changed the party at all.

This was a watershed. Do not now expect party political broadcasts to be filled with grainy black-and-white film of uncollected and rat-infested dustbins during the 1978-79 winter of discontent. That saga began before the new crop of 18-year-olds who will be on the electoral register by May 1997 was even born.

To all that, the Conservatives yesterday said a regretful, but unmistakable farewell. They will henceforth spend their newly and mysteriously acquired millions on seeking to persuade electors that Mr Blair has indeed changed his party, but not into the harmless imitation of Toryism that, for the past few days, the Labour leader's backbench critics have been claiming it has become.

Instead, the message for which Conservative Central Office and its PR troika of Maurice Saatchi, Sir Tim Bell and Peter Gummer secured endorsement yesterday is that Labour poses the country a new threat for new times.

This is a stunning acknowledgement of Mr Blair's dominance - so far - of the electoral landscape. It accepts that the new cannot now be detached from new Labour. The focus groups of now disaffected voters - who were Tory in 1992, and in whom both the main parties have been obsessively interested for many months - now apparently use the term "new Labour" without self-consciousness. It also draws conclusions, unpalatable for many Tory activists, from Mr Blair's triumphant rewriting of Clause IV and the long list of subsequent policy reversals that culminated in last week's unflinching mine-clearing operation over Scottish and Welsh devolution.

The analysis that Mr Blair is different but the party remains the same just won't run. If it were right, Mr Blair would now be confronting some rather more menacing public opponents than the backbencher Paul Flynn. And he would not be planning to put Thursday's revisionist Road to the Manifesto document to a ballot of the party's full membership with almost total confidence.

Ministers were reluctantly forced to accept all this yesterday, implicitly admitting that it had taken them two years to agree on how to attack Mr Blair.

Nevertheless, Labour would be foolish to ignore the approach agreed yesterday. Just as the notion of Britain as an Enterprise Centre for Europe sought to bring some order to the confusions of post-Thatcherite Conservatism, so the new anti-Labour strategy will be to try and map out an internally coherent set of answers to the daunting question of how to make Blairism threatening.

The constitution is one example cited with enthusiasm at Central Office. Hard as it is, Tories will try to demonise Charter 88 as the Nineties equivalent of CND. By depicting the Labour leadership as fellow travellers to a metropolitan clique of root-and-branch constitutional reformers, the summer campaign will seek to fix the prospect of a Blair premiership as one that would preside over what has already been labelled for internal Tory purposes "the last British Government".

The Tories, for example, are preparing to argue that a Bill of Rights will empower the unelected judges at the expense of a democratic Westminster. And through a combination of Labour's devolution plans and the Blair promise not to be isolated in Europe, the Tory tactic will be to try and make stick the charge that Blair is undermining the very unity of Britain that he claims a mandate to strengthen.

Another is the economy. No longer running the fantastic claim that Blair intends to deliver the country back to the union barons, the Tories will instead argue that the national minimum wage, Labour's espousal of the Social Chapter, and the still-cloudy notion of a stakeholder economy are designed to arrest and temper the global process of change which the Tories will argue they alone are capable of embracing. The argument that a minimum wage relieves the taxpayer of subsidising unscrupulous employers though the social security system will be turned on its head. Instead, the minimum wage will be suborned as the new threat to inward investment, jobs and competitiveness. "New Labour," the mantra will go down the ranks, "new interventionism".

So also with tax and spend. In tacit acknowledgement of Blair's ruthless success in applying the golden rule of not spending more than you can save, Tory researchers are now concentrating on what Labour has not yet explicitly ruled out - such as dozens of spending pledges in earlier policy documents which they believe Blair cannot disavow without further internal tremors.

What's more, ministers are considering an explicit promise not to raise standard rate income tax in the next Parliament and then challenging Labour to match it.

A lot of this is unedifying, or not yet convincing, or both. To begin to work, it needs a subtlety that utterly failed to inform Stephen Dorrell's far-fetched hint yesterday that constitutional reform could even threaten 250 years of civil peace. But the Tories have at least settled on an anti- Blair strategy to road-test until the party conferences. If nothing else, it is a reminder for Labour of the fireproofing that it has still to put in place. It's going to be a long hot summer.