John Armstrong: 'Mr Angry' pulls minister down to Earth

Judith Collins can count herself lucky. Very lucky. Ministers have found themselves booted out of the Cabinet for much lesser crimes than the truly cardinal sin of misleading the Prime Minister.

John Key would have been well within his rights to demote her to National's backbenches after she admitted that she had not told him the whole story regarding her visit to China last year and her meetings with Oravida, the company whose directors include her husband.

Had Key been consistent in terms of punishing ministerial misdemeanours, he would have been ripping up her ministerial warrant and looking to someone else to run her Justice and ACC portfolios.

Not doing so has put the Prime Minister at risk of looking weak and inconsistent.

Key deliberately sought to counter that possibility by unceremoniously kicking down the ladder to Collins' lofty perch, from which she had been lambasting all and sundry who had the audacity to question the constitutional propriety of her behaviour and suggest she was guilty of a serious conflict of interest.

It takes a fair degree of provocation from someone or something for Key's temperament to shift from Mr Amenable to Mr Angry. But he was seething as he delivered a very blunt and very public dressing-down of his front-bench minister.

He also delivered a very public notice that she was now on a final warning and that he would not want to be in her shoes if there was any repeat of the serious blurring of the lines between what is and is not acceptable from a minister.

Caution still prevailed, however. Sending Collins into exile would have been a very big call - one which might have been seen as harsh given her otherwise impeccable record as a minister.

It would have risked turning an MP who is popular in the wider National Party into a potential martyr and allow her to become a magnet for any caucus and party dissent - plus the freedom to lay out a vision of the direction she would take National if, as is probable, she challenges for the party's leadership when Key eventually steps down.

Leaving her where she is has its advantages. She is a highly effective minister who has handled difficult portfolios such as Police and Corrections with aplomb.

Equally worrying for those who would push her barrow has been her refusal until yesterday to take a step back, draw a long breath and admit that, yes, she had made some mistakes which she now regretted and for which she apologised.

That would have instantly ended the fun Labour has been having. Instead, Collins allowed what she described as "a 20-minute cup of tea on the way to the airport" to turn into a 10-day-long distraction from the problems Labour has been having.