Andrew Grice: How Cameron's clever trick turned into the second Conservative wobble of 2010

It seemed a clever trick at the time. David Cameron knew that Gordon Brown would be holding his monthly press conference at 11am on Monday last week, and so he called his for 9.45am.

It doesn't look quite so clever now. Mr Cameron attacked Labour for not getting a grip on the £178bn public deficit and said it should "tear up" its spending plans for the financial year starting in April, when the Government will spend £30bn more than in the current year. Comparing Britain to crisis-hit Greece, he said Labour must "start now" to reduce debt. "It's like a credit card – the more we spend and the longer we wait to pay off our bills, the worse it can get."

With hindsight, the Tory leader should have waited until after the official figures on economic growth had been issued the following day. He appears to have believed City predictions of 0.4 per cent growth in the final three months of 2009. In the event, there was a fragile recovery of just 0.1 per cent.

Although the figures were hardly a shot in the arm for Gordon Brown, they created a headache for Mr Cameron. While the Bank of England and financial markets want to see a clearer Labour plan to reduce the deficit, most economists agree that it would be folly to turn off the public spending tap when there is a risk of a slide into a double-dip recession.

Mixing with businessmen at the World Economic Forum in Davos, Switzerland, Mr Cameron felt the need to rebalance his Monday remarks in the light of the feeble growth figures. "Early action does not have to be particularly extensive, but it's got to be early," he told British business leaders.

Labour knows an open goal when it sees one. It converted Mr Cameron's remarks into a U-turn, contrasting them with his previous comments and a recent pledge by the shadow Chancellor, George Osborne, for an emergency Budget within 50 days of the election that would include mid-year spending cuts.

On Sunday Mr Cameron told the BBC he did not plan immediate "swingeing cuts", adding: "We're talking about making a start in reducing our deficit."

The Tories dismissed his remarks as a clarification and emphatically denied any change of policy. They insist that they have never been committed to big early cuts and have always made clear that any reductions would be co-ordinated with the Bank of England in order to keep interest rates low.

But Labour scented blood and sought to twist the knife by calling a press conference chaired by Lord Mandelson yesterday. Warning that Mr Cameron's household economics were "illiterate", the Business Secretary warned immediate cuts would strangle the recovery at birth.

The Tories professed to be relaxed, but they are not. It is the second apparent wobble this year. Last month Mr Cameron admitted he "messed up" over his party's pledge to reward marriage in the tax system. The Tories hoped that would be a one-off. Now, in Labour's eyes at least, they have messed up on a much more central issue: when to start the cuts that all parties admit are inevitable.

Labour always hoped a relatively untested Tory leadership would crack under the pressure of an election, when intense media scrutiny can magnify any change of emphasis. Team Brown now thinks it is happening.

The Tories are desperate to nip the impression in the bud. But they are also fighting off dangerous rumours of tension between Mr Cameron and Mr Osborne. The shadow Chancellor is less keen than the Tory leader on aiding marriage in the tax system. Some insiders claim that Mr Osborne is more keen on early, bigger cuts. Speculation along those lines has been fuelled by Mr Cameron's clarification.

Mr Osborne remains Mr Cameron's closest ally and, whatever the private debates between them, they are united in their determination not to fall out in the way that Mr Brown and Tony Blair did. Recent events show they need to choose their words – and the timing of them – very carefully.

This latest setback is deeply frustrating for the Tories. They claim, with some justification, that it is Labour who is split over cuts. Mr Brown and the Schools Secretary, Ed Balls, are instinctive spenders but have been persuaded to talk the language of cuts – starting in 2011, not 2010 – by the Chancellor, Alistair Darling, and Lord Mandelson.

Ironically, as Labour turns up the volume on cuts, the Tories are turning it down. Perhaps they will meet in the middle. The latest episode suggests the differences between the two main parties are not as big as they tell us.