WHY is the BBC, which is supposed merely to report the news, so often nowadays creating it? To answer that question, we need to go beyond the salacious details of the Unnamed Presenter — or thoughts about whether the BBC needs to improve its external complaints procedure. Instead, we must consider the somewhat overlooked remarks of the BBC’s departing chairman.

Richard Sharp resigned as chairman of the BBC in April — after failing to disclose potential perceived conflicts of interest — but he actually left the post only last week. His parting shot was to suggest that the BBC licence fee should be replaced by a mandatory broadband tax — or by a variable levy in the style of council tax, so that the wealthy pay most.

The idea did not cause much of a stir, perhaps because Mr Sharp was on his way out. But his successor, whether a Conservative or a Labour nominee, he observed wryly, would have a “target” on their back.

Yet, incoming fire comes from one side more than the other. That is clear in Jack Thorne’s thought-provoking new play When Winston Went to War with the Wireless (Arts, 23 June). During the General Strike of 1926, industrial action had closed the nation’s newspapers. The only outlet for news was the government-run British Gazette. The play tells the story of how the man who ran it, Winston Churchill, fought to bring the nascent BBC into line with the Gazette’s one-sided propaganda.

In the programme, Andrew Marr writes of how, as BBC Political Editor, he regularly received menacing calls from Downing Street, and draws an interesting distinction between a state broadcaster and a national broadcaster, where the latter is sustained by an arm’s-length funding mechanism such as the BBC licence fee.

Yet, such a system can operate only according to what our great constitutional historian, Lord Hennessy, dubs the “good chap” theory. The unwritten British constitution relies on the fact that all those involved observe certain basic decencies — of the kind that have been junked by the politicians of the Boris Johnson era: knaves who lie as blithely to the monarch as to the voters.

It is interesting that the latest vehicle for bashing the BBC is The Sun, a paper owned by Rupert Murdoch, the man who went to Chequers and told Boris Johnson, as he dandled the PM’s baby on his knee: “Boris you’ve got to get rid of the BBC, it’s eating my lunch, they’ve got a website, they’re a publisher, it’s not competitive” — in words reported by the then PM’s sister, Rachel.

What you have to remember, a former editor of The Sun, David Yelland, said this week, is that all the newspapers that so enjoy attacking the BBC have both an ideological and commercial interest in doing so. They see it either as a media rival or as an obstacle to the “Foxisation” of British television news. Very few “good chaps” in that quarter, either.

When trust goes, as the philosopher Onora O’Neill has pointed out, our only recourse is to rules. The next government, therefore, must find a way of iron-cladding that arm’s-length principle. In the play, John Reith preserves the BBC at the cost of his personal integrity. There must be a better way than that.