Ed Miliband's pledge to reintroduce the 10p tax rate has left the Tories with a dilemma. Having previously hinted  that they might adopt the measure, which was first proposed  by a Conservative MP, Robert Halfon, do they seek to match Miliband's offer or do they reject it?
It now looks as if George Osborne has settled on the latter option. In his interview  on ITV's The Agenda last night, the Chancellor declared that the coalition had "a better policy" - "a zero per cent tax rate". He pointed out that the increase in the tax-free personal allowance from £6,475 in 2010 to £9,440 (from this April) had already compensated all of those who lost out from Gordon Brown's abolition of the 10p tax rate, adding: "We've taken a million people out of tax altogether so I would say a zero per cent tax rate is going to be a little bit more attractive at an election than a 10% tax rate and that's certainly been our priority."
Coming from the man who remains the Conservatives' chief election strategist, it was a significant statement. The Lib Dems have long made it clear that they will go into the next election promising to raise  the personal allowance to £12,500, so that no one on the minimum wage pays any income tax. Osborne's words suggest that the Tories are now more likely to match this offer than are they to cut the starting rate.
It's not an approach that will please all Tory MPs. Halfon is fond of quoting former Conservative chancellor Nigel Lawson, who began his time at the Treasury by raising personal allowances but later reversed direction. He later explained: "I wished to create a large constituency in favour of income-tax reductions. The last thing I wanted to do was to reduce the size of that constituency by taking people out of tax altogether." But the imperative for the Tories to differentiate themselves from Labour now trumps this concern.
With two years of the parliament remaining, the tax threshold is just £560 from the coalition's target of £10,000 after a larger-than-expected increase in the Autumn Statement. If Osborne chooses to pull a rabbit out of the hat on Budget day (as he usually does), one wonders if it will be to meet this pledge ahead of schedule. Having unambiguously rejected a mansion tax and now cast scorn on the 10p tax rate, the Chancellor has shown that he has no intention of dancing to Labour's tune.