Given that it centres around potential ministerial impropriety, is the prime minister's decision to go straight to the police commissioner about a current investigation appropriate?

This is the sequence of events. Angus Taylor, federal cabinet minister, used a doctored document to publicly accuse Sydney Lord Mayor Clover Moore of being a hypocrite on climate change because her councillors spent, allegedly, $15 million on travel in a year (the real figure was about $6000). The document was a forgery, but Taylor insisted his office had downloaded it from the council's website. That's been shown to be wrong.

As far as Taylor is concerned, that's it. He has denied any impropriety by him or his office, but not explained where the fake document came from. FOI requests for correspondence relating to the train of events have been refused and he hasn't answered questions in parliament about it. The mystery persists.

Yesterday, it came out that the Labor Party had written to the NSW Police and that the police have launched an investigation. The nature of that has not been revealed; presumably they're looking at some form of potential forgery or fraud offence.

When asked about this development in question time, Scott Morrison said it was news to him. He said he would speak directly to the NSW Police and find out. He came back later in the day to announce this:

I have since spoken with the NSW Police Commissioner about the investigation and the nature and substance of their inquiries which he advised me were based only on the allegations referred by the shadow attorney-general. Based on the information provided to me by the commissioner, I consider there is no action required by me.

The action that Labor was demanding was that Morrison stand his minister down while he is under an active police investigation, in compliance with the ministerial guidelines. These are not binding, but it is conventional that a minister stands aside from their office when their conduct is under a serious cloud. Most recently, the Liberal minister Arthur Sinodinos stood aside voluntarily during an ICAC investigation into him (which ultimately exonerated him).

The conventions of ministerial responsibility have become progressively honoured in the breach in recent years, so it's no real surprise that neither Taylor nor Morrison proposes to take this matter seriously or pay the public the respect of providing an actual explanation of what happened.

However, there's something even weirder here: the prime minister's open acknowledgement that his first instinct was to call up the police chief for a personal chat about the current investigation of potential criminal conduct by one of his cabinet ministers.

If that sounds a bit off to you, that's because it is. Whatever the status of the investigation may be, and whatever its prospects of leading anywhere are, it is in the hands of an agency of the executive government of the state of NSW. It is axiomatic that the police are required and expected to function with independence, unaffected by political influence.

So, is it appropriate that the prime minister should go straight to the police commissioner and ask him for details of a current investigation into his political ally and a member of his government? Is it appropriate that he should blithely tell parliament and the country that that's what he's doing? Is it appropriate that he should then announce, essentially, that "I've had the word from the cops, it's a beat up, it's all going to go away"?

None of those things are appropriate. Morrison should have made a discreet inquiry through proper channels to confirm the report that the police were investigating Taylor. He should have consciously ensured that he not ask about the details of the investigation nor do anything that could suggest he was trying to influence its course or outcome. Having confirmed that Taylor is under active investigation, he should have stood him down immediately and advised parliament accordingly.