His mood was possibly sharpened by the appearance of the fellow he replaced as Speaker, Harry Jenkins, sporting his own silvery bow tie. The view around Parliament was that Mr Jenkins was gently taking the mickey.

Resplendent in black robe, white bow tie and barrister's tabs, fresh from his latest ceremonial procession to the House, Mr Slipper decided to enforce his edict at the first opportunity yesterday.

Prime ministers and their ministers have traditionally spent large portions of every question time avoiding what most people would recognise as a semblance of relevance in responding to questions.

Opposition Leader Tony Abbott opened combat with his favourite subject: reminding Ms Gillard that she had promised during the last election campaign that there would be no carbon tax. Now she was introducing just such a tax and had admitted she had made mistakes she regretted, would she ''rescind her deception'' and put aside the tax until she took it to the next election?

Mr Slipper ordered Mr Abbott to withdraw the word ''deception''. But when Ms Gillard launched into her answer the full might of the Speaker was exerted.

''Putting a price on carbon was the right thing to do and I stand by it,'' Ms Gillard began, her eyes turning flinty in the style she has assumed following the Great Unpleasantness of the past week.

And then, in her well-practised manner, Ms Gillard turned the question on its head and got stuck into the opposition, declaring that Coalition MPs might like to explain why they had promised to introduce a price on carbon during the 2007 election campaign. As she reached full throttle, Mr Slipper called for her to be ''directly relevant'' to the question.

Ms Gillard sailed on, and the Speaker hollered again for her to get back to the subject at hand.