Last time I wrote about the BBC in the aftermath of a controversial opening monologue by Emily Maitlis – which was less than a month ago – I pointed out something which ought to worry Corporation executives.

Contrary to the claims of some of its critics, there hasn’t been a widespread collapse in trust in the BBC as a whole. But there has been a sharp fall in trust in its current affairs coverage amongst Conservative voters.

If the BBC wants to retain its position as a purveyor of shared experiences to the nation, it needs to be able to speak to the whole nation. At a time of deep partisan divisions that task grows harder, but also more important.

To breach partiality once may be regarded as misfortune, as Lady Bracknell might put it. But to do so twice looks like carelessness.

But was it carelessness? One BBC source put it to me that Newsnight has featured opening remarks by the host since at least the era of Jeremy Paxman, and that it isn’t difficult to phrase them in a more judicious fashion. Yet this simply makes it less likely that a veteran such as Maitlis, and the experienced team at a flagship programme, keep tripping these landmines by accident.

Compounding the issue further is the unapologetic stance adopted by Newsnight personnel online, not least Maitlis’ retweeting of a clip of her monologue after the official BBC account deleted it. Her colleague Lewis Goodall has also been deleting tweets after doubling down on the claim that Dominic Cummings broke the rules.

The Corporation, after reportedly receiving tens of thousands of complaints, put out the following statement which acknowledged that Maitlis’ opening remarks breached its editorial guidelines, focusing specifically on two elements:

“It said that ‘the country’ was ‘shocked the government cannot see’ Dominic Cummings broke lockdown rules; that he ‘made those who struggled to keep the rules feel like fools’.

“But there are some who do not share this opinion, nor think that the issue is a ‘scandal’ or the Prime Minister has displayed ‘blind loyalty’.”

Other sections were arguably even more nakedly editorial. It’s difficult to see the impartial news case for saying that Cummings “tagged the lazy label of ‘elite’ on those who disagreed”. The word ‘lazy’ is purely a pejorative, personal judgement. Likewise, it is hard to defend as a mere teeing up of the issue a statement which tells the subject what they ‘should’ be doing.

Such incidents will only accelerate Conservative disaffection with the BBC’s current affairs programming, a development which will threaten the BBC’s role as a unifying national broadcaster and reduce the ranks of its allies in the Government.

But that isn’t the only troubling aspect of this story. Just as concerning, at least, is the number of progressive commentators who appear genuinely unable to see why some of Maitlis’ remarks were so problematic – and even that the BBC pulled her from the show in response to Government pressure.

This is the other side of polarisation: as one side becomes more sensitive to criticism of an outlet perceived to be unfriendly, the other becomes more sensitive to criticism of said outlet. Such cheerleading can do as much to corrode truly impartial news values as hostile criticism by reinforcing and rewarding presenters and producers who push the partisan envelope.

In Britain it is fashionable to hold up Fox News as the ur-example of what we’re trying to avoid, but its liberal counterparts have also played a vital role in insulating huge sections of the American public from each other.

What can be done? The BBC has brought in a former executive to review the way its staff employ social media, which may help to stem the ‘Sky Views’ problem of presenters undermining their on-camera impartiality with their off-camera conduct. The team at Newsnight have been reminded of the guidelines, although it remains to be seen what action might be taken in the event of a third breach.

But perhaps one important step would be drawing much clearer lines about using BBC news shows as podia, even for uncontroversial takes. As we noted last time:

“It’s all very well letting Andrew Neil inveigh against ISIS – who supports ISIS? – but it does set a precedent which makes it harder to prevent his colleagues indulging in similar tactics on more divisive ground.”