But the more that Mr Morrison tried to explain what he did - "I was steering the ship in the middle of the tempest," he said at one point - the further he dug himself into political and reputational quicksand.

Were Mr Morrison still in government he would face calls to resign as PM on the simple grounds of misleading the parliament - which by omission he certainly did. As an opposition backbencher and a servant of the Liberal Party, the honourable course for Mr Morrison is to resign from politics.

The scale of this controversy and the time for which it could run means that an early-term by-election is the least of the Coalition's worries.

At this stage, however, Mr Morrison appears determined to try to tough it out. If he does stay, he would at least be around to front whichever parliamentary committee, or committees, are charged with investigating this sorry and ill-advised saga.

It would be wrong to call this a constitutional crisis, because the issues involved are now no longer "alive", thanks to the May 21 election that ended the Morrison government and a decade of Coalition rule.

However Mr Morrison has certainly embroiled the Governor-General, David Hurley, whose involvement was confirmed yesterday by the Department of Prime Minister and Cabinet, which published the four relevant instruments of appointment, signed by the governor-general, on its website.

There can be no peacetime rationale for accumulating secret powers.

It is not the legality or otherwise of his actions, but rather their secrecy. It alone renders his behaviour irredeemably wrong.

For many years Mr Morrison was always more than ready to lecture his political opponents - and often the media - on ethics.

But surely ethics must start with honesty towards the electorate - towards the people you represent.

It is an honesty Mr Morrison did not show regularly as the Prime Minister, and an honest he is reluctant to recognise now.