The postmortem on how we got ourselves into this mess will be long and complex. But at its heart will lie this simple proposition: good democracy relies on good information.

What does “good information” look like? We might say: information that is not only true but also believed. And therein lies the problem. We’re no longer very willing to believe almost anybody. Most surveys of trust find very little faith in what government or politicians tell us. But there are also extraordinarily low levels of trust in most media. Nearly two-thirds of people say they can no longer tell good journalism from rumour or falsehoods. This is, to put it mildly, a disaster. Into this vacuum of unbelief and mistrust step liars and peddlers of fantasies. By all means call another referendum or election, but what makes anyone confident that the electorate will make a “better” decision than last time round? And I don’t just mean Brexit.

If you are going to put a crucial decision on the future of Britain to a vote of citizens it’s pretty obvious what the proper function of the press should be: to arm them with unvarnished facts on both sides of the argument. We might add: don’t pretend a complex question is a simple one. And: by all means tell us your own view, but save that until you’ve given us the facts.

Etonians, unironically, give a kicking to 'the elites' with a winking eye on next day’s tabloid headlines

For the past four years – you might say much longer – this is not how much of the British press has behaved. Several newspapers have done the opposite. They pretended Europe was a really simple question. They did not bother to present both sides of the argument. And they appeared overwhelmingly keener on shouting their own views before presenting straight news.

The prime minister himself is at the heart of this story. His Brussels years of ever more inventive Euro “scoops” morphed into years as editor and columnist in the service of the tax-shy Barclay brothers. The Telegraph reciprocated by becoming Johnson’s greatest cheerleader in his rhetoric-over-evidence rush to lead a do-or-die Brexit. Today it’s often hard to tell whether he thinks he’s dashing off a column or governing the country.

But there will, in time, be so much more to examine. The then proprietor of the Express, a former pornographer, writing a cheque for £1m to Nigel Farage at the start of the referendum campaign – thereby effectively signalling the end of the Express as a newspaper. The Sun printing a BeLeave in Britain poster – and duly having to register it as a £97,000 donation to the Leave campaign. Why should the public trust “proper” news when journalists turn propagandists?

And then the bullying. The front-page exhortations to “crush the saboteurs”, the denunciations of the “enemies of the people” and the Brexit mutineers. “Dissident” MPs displayed like targets on front pages as though the murder of one of their colleagues counted for nothing. And, lately, the persistent anonymous feeding of anonymous No 10 titbits to journalists, who breathlessly rush them on to Twitter with barely a care as to whether they’re actually true.

We could add the mirroring of the current crude demotic political discourse. Quentin Letts, moonlighting in the Sun when he is not entertaining Times readers, calls Lady Hale a “beady-eyed old nanny goat”. Why?

Letts went to a decent private school, attended two world-class universities and – when not putting the boot into people who do not conform with his own idea of what the establishment should look like – leads a bucolic life as a deputy church warden in Herefordshire. In the past such figures would have seen it as their role to help people without their privilege to become better informed. Now, Dacre-trained in attack dog menace, he pulls on his bovver boots and joins them.

Posh boys being populist is one of the hallmarks of the current state we’re in. Etonians, unironically, give a kicking to “the elites” with a winking eye on next day’s tabloid headlines. Oxford graduates sneer at experts. Dominic Cummings (private school and Oxford) holds most manifestations of post-Enlightenment values in contempt. Letts lets rip with his own form of class war.

The new elitism is a deadly form of condescension. Sun readers aren’t there to be informed. Entertained, yes. Inflamed, yes. Infuriated: certainly. But not well informed.

Interestingly, the Mail, under a new editor, is quietly turning itself into a much more nuanced paper, willing to do justice to more than one side of an argument. An editorial on Hale was notably reasonable – miles away from the finger-jabbing fury of the previous regime. Sales seem to be holding up just fine (and, I’m told, more than 200 advertisers have returned).

Most foot soldiers in journalism do the job because they absolutely believe in the role of good information in good democracies. Something is stopping them: and the sooner we can fix that the better.

Alan Rusbridger, a former editor-in-chief of the Guardian, is principal of Lady Margaret Hall at Oxford and chairs the Reuters Institute for the Study of Journalism