Having branded the Tories with responsibility for a string of tax rises and raised the spectre of VAT on food, the critical focus is being tightened on Mr Major. Honest John is being called a two-faced liar.
Labour's ad agency had hoped to run an even more personalised and negative campaign, portraying the PM as a spineless, dithering version of the Mr Men. Contrary to initial press reports, this cruel idea was vetoed not by Tony Blair but by trustees of Roger Hargreaves, the creator of this children's cartoon.
Although disappointed by that refusal, the agency BMP DDB feels its alternative could prove just as effective. Three 48-sheet posters branding the Conservative leader as a two-faced liar will have high visibility nationwide from today. Labour has bought what is known in the trade as the "Benetton package" - prominent, quality sites throughout the country.
The assault comes as a fresh independent survey has revealed that Labour's ads are packing considerably more impact among former Conservative voters than scaremongering slogans such as "New Labour, New Danger".
A poll conducted earlier this month by Opinion Research Business for the stockbrokers HSBC James Capel found that only 8 per cent of those who have strayed from the Tories since 1992 have been persuaded to reconsider their political allegiance by M&C Saatchi's attempts to demonise the opposition.
More than half (55 per cent) say the campaign has made no difference while 37 per cent say it has made them even less likely to vote Conservative.
The ORB/Capel poll found that two anti-Tory messages devised by Labour - "Next time VAT on food" and "22 new taxes" - were recalled by more voters than any created by the Conservatives, including the infamous "demon eyes" attack on Tony Blair, which was recalled unprompted by just 12 per cent of the survey sample.
These results reflect the findings of a focus group convened recently by the Financial Times in conjunction with the ad agency FCB. Both obviously delight BMP DDB, which was re-entrusted with Labour's political advertising shortly after Mr Blair became leader.
Its chief executive is Chris Powell, whose younger brother Jonathan is Mr Blair's chief of staff. (Another sibling, Charles, was Margaret Thatcher's top foreign policy adviser, but he even pronounced the family surname differently: Pow as in toe.)
Having slipped from favour in the bitter aftermath of the 1992 election defeat, Chris Powell and his pro-Labour creative chums are firmly back in favour. The Labour account is handled by a small unit drawn from BMP's 350-strong staff and a few other sympathisers from elsewhere in adland. They operate under a higher degree of security than their colleagues, many of whom are Conservatives.
BMP is Britain's fifth-biggest agency and boasts an impressive portfolio of blue-chip clients.
As the election could be called any day now, BMP has a range of posters and plans for party political broadcasts locked away in a secret vault at its headquarters, a converted building near Paddington Station that was built by the Great Western Railway.
Convinced that its campaign is on the right tracks, it is expected to stick with the same economic theme all the way to polling day