But there he was yesterday, out the front of Parliament, tempering other more populist remarks with a few frank and sobering admissions.

A capacity for straight talk is the Opposition Leader's great political strength - and probably the biggest risk he takes. But also compelling is the impact of his style on his opposite number. In the face of a plain-spoken, populist warrior with a gift for the cut-through line, Kevin Rudd is still struggling to sharpen his own sound bites.

The Prime Minister admitted as much yesterday, arguing that while the government may have been frantically busy, ''our challenge is to communicate more effectively that which we have done''. You can say that again.

From the moment Mr Abbott was elected in December, it was clear the Coalition would run a scare campaign on the impact of Labor's emissions trading scheme on household costs.

You might have thought senior government figures would have spent the summer perfecting punchy sound bites of their own in anticipation of this week's clash. Clearly some work had been done - Mr Rudd's lines yesterday were tighter than last year, including his hit on Mr Abbott's plan as a ''climate con job'' and the barb that the Opposition Leader had changed his climate policies more often than he'd ''changed his undies''. But Labor still has a long way to go to neutralise Mr Abbott's imprint with voters on the ETS.

On even the obvious - how much extra bread and milk is going to cost under an emissions trading scheme - Mr Rudd was initially caught without an answer.

Asked on Channel Nine about bread, he hedged: ''$2.40 at the no-brand level, up to $4, $4.80 for some of the better brands,'' he said. And then he ducked: ''I don't run every bread manufacturing outfit in the country.''