Reader, I let you down. I tried to strangle the career of Greta Thunberg before she properly got going, and I failed.

I was deputising for Nigel Farage at the European Parliament’s “Conference of Presidents” — the meeting that really shapes that institution’s forward agenda — when the leader of the Greens, Philippe Lamberts, proposed inviting this then relatively unknown schoolgirl to come and give a speech.

This must have been in autumn 2018, not long after Thunberg had started sagging off school on Friday afternoons to protest against climate change and encouraging her peers to do the same. I spoke against Mr Lamberts’ proposal, saying that it seemed like a ridiculous gimmick designed to advantage Green candidates in the following spring’s MEP elections (a line that I hoped would cause other group leaders to support me).

But Lamberts fixed me with his tight raisin eyes and after admonishing me for characterising any crusade aimed at saving the planet as gimmickry, he easily carried the room.

The following April, Thunberg did indeed address MEPs, garnering massive media coverage right across Europe in the process. “My name is Greta Thunberg. I am sixteen years old. I come from Sweden and I want you to panic. I want you to act as if your house was on fire,” she began.

It is hard to dispute that in the two and a half years since then, she has been instrumental in spreading alarm about the extent and speed of climate change. The Greens did indeed make substantial gains at the 2019 European elections, while the conventional centre-left and centre-right groups chalked up big losses (oh dear, what a shame, never mind).

Thunberg has upped the rhetorical ante still further by mocking “so-called” world leaders

What has been most striking is the evolution of Thunberg from schoolgirl tyro to global superstar, along with her ruthless use of this new status to cow critics into silence and marginalise sceptics. It is not unusual for a political actor to wish for no form of media coverage other than hagiography. It is, however, most unusual for the political media to grant that wish.

In autumn 2019, during her famous “How Dare You?” speech, she browbeat representatives at a UN Climate Action summit, by telling them: “You have stolen my dreams and my childhood with your empty words.” That was a line that seemed to me to follow the same disquieting logic often deployed by those committing abusive acts (“you made me do this”).

Her other most famous act on the public stage was the look of cold fury she gave when staring at Donald Trump — a frown so intense that it is a wonder the Orange One was not turned into stone on the spot.

This week, Thunberg has upped the rhetorical ante still further by mocking “so-called” world leaders in a speech at the Youth4Climate conference in Milan.

As Alok Sharma, the Cabinet minister in charge of preparations for the COP26 climate conference in Glasgow, watched — gawping, goldfish-style — via a remote video link, Thunberg mocked the British government’s soundbites: “Build back better blah, blah, blah. Green economy by 2050 blah, blah, blah. Net Zero by 2050, blah, blah, blah.

“This is all we hear from our so-called leaders. Words. Words that sound great but so far have led to no action. Our hopes and dreams drowned in their empty words and promises… they have now had thirty years of blah blah blah,” she added, to the obligatory backdrop of whooping and applause that now accompanies any platform utterances she makes.

Fair play to her, one might think, for turning herself into such a compelling and effective delivery system for the most strident messages of ecological campaigners.

One shudders to think what acts she would be prepared to justify

In fact her claim of “no action” against climate change over the past 30 years is risible, especially when directed at the United Kingdom, which has cut its carbon emissions further and faster than almost anybody thought possible and at considerable expense to households in the form of levies on energy bills.

I suggest it is now incumbent on the many Greta-worshippers in British broadcast media — particularly within the BBC — to subject her claims and utterances to the same sceptical scrutiny they deploy against other major political figures.

In her Milan speech, Thunberg seemed to fully adopt the mindset of a fanatic when demanding “drastic annual emission cuts unlike anything the word has ever seen”.

“We will have to change…we can no longer let the people in power decide what is politically possible or not,” she said. Those would be the people who went to the trouble of getting elected, then. The ones with democratic legitimacy.

For Thunberg to be calling for them to be side-lined — presumably forced to hand the reins of real power over to her and her fellow travellers to implement “drastic” measures that curtail freedoms just because they know best — amounts to a lurch into outright totalitarian thinking.

Given the overwhelming importance of the cause Ms Thunberg has identified and her own fanatical devotion to it, one shudders to think what acts she would be prepared to contemplate or justify were she ever to get her way. In a rational political climate, Ms Thunberg would now be presented as an extremist.

Is it really too much to hope that come COP26, Alok Sharma and his boss will at least avoid the indignity of fawning all over her in a doomed bid to obtain a Greta stamp of approval?