When Sydney’s lord mayor, Clover Moore, wrote to the minister for the environment to inform the federal government that her council had declared a climate emergency, she probably wasn’t expecting events to unfold in such a spectacular fashion.

The Labor party is now calling for a New South Wales police inquiry into a fraudulent document at the centre of this saga, the City of Sydney council has called in IT experts to examine its website, and the energy and emissions reduction minister, Angus Taylor – who relied on the false document – is under serious pressure to explain.

But the most unfortunate outcome of this affair is that it will once again diminish the already fragile trust in both politicians and journalism. In this era of fake news, the fact that a politician sent a document containing false figures to a journalist, who then relied on it to publish a story, does no one any favours.

The story starts with Taylor’s reply to Moore after she wrote to him on 29 September to inform him the council had declared a climate emergency. Taylor’s response included a patronising lecture about Moore’s travel spending.

“You might be interested to know that there are many practical ways local councils can take real and meaningful action to reduce their carbon emissions,” Taylor wrote. “One way was to limit unnecessary air travel.”

Much to Moore’s surprise, he told her that her travel spending was $15m.

Perhaps not so surprising is that the letter was given to News Corp tabloid the Daily Telegraph, which repeated his claim.

This figure is wrong. The 2017-18 annual report on the website shows that councillors spent $4,206.32 on domestic travel and $1,727.77 on international travel. In total, council employees spent $229,000.

Common sense says the $15m figure is wrong too. The City of Sydney employed 1,839 staff as at 30 June 2018. Most of those are workers in the relatively small CBD council area as gardeners, childcare workers, parking inspectors, librarians and planning staff. To spend that much, each staff member would need to spend more than $8,000 a year on travel.

The Telegraph journalist who wrote the story that included the incorrect figure, faced with a furious lord mayor, provided the council with the page out of the council’s own annual report on which she had relied. She told council in an email, which the Guardian has seen, that it had been sent to her by Taylor’s office, and that it had told her it had been downloaded on 6 September from the council’s website. The only problem was the figures were wrong and the document provided by Taylor’s office had somehow been doctored.

We can rule out the journalist as the source of the false document, because Taylor used the same figures included in the false document – $14.2m for domestic travel and $1.7m for international travel – in his letter to Moore.

The council has also done its best to answer questions by providing its metadata, which reveals when a document was created and when it was last altered. The annual report in question was last altered on the same as the day it was put up last November.

And what did Angus Taylor say? He has refused to answer any questions put to him by the Guardian.

Early on Thursday he accused Moore of peddling “a conspiracy theory” and gave her another lecture about flying to Paris to attend a Women4Climate conference in Paris last March, which Sydney is hosting in 2020. (It seems it’s OK to solicit sporting matches in Sydney, but not women’s climate conferences.)

But the stakes are raised when it comes to answers in parliament where misleading is a serious matter. Taylor took a minimalist approach. When asked about a “forged document”, he answered that he did not accept the premise of the question.

The only real answer we got was this: “The document was drawn from the City of Sydney website and it was publicly available.”

He then went on to “reject the bizarre suggestions and assertions being peddled by those opposite” and to accuse them of “a smear”.

This answer tells us little: we don’t know who downloaded the document, what it contained at that point, whether it was altered and by who.

Taylor, who used to be the minister for digital transformation, would know enough about digital documents to know that he could quickly clear this up by providing the metadata of his document.

Instead the NSW police will be asked to investigate whether there has been a breach of the criminal law.

“The creation and/or knowing use of a forged document in an attempt to influence a public duty is a serious indictable offence under New South Wales law, punishable by up to 10 years in prison,” the leader of opposition business, Tony Burke, told parliament. Failing to report the same is too.

In the meantime the corrosion of public trust will continue. The Daily Telegraph is rightly furious at being misled. The public should be furious too. The answer lies in the hands of the Morrison government. All it has to do is take a look.