If our politics is becoming less rational, crueller and more divisive, this rule of public life is partly to blame: the more disgracefully you behave, the bigger the platform the media will give you. If you are caught lying, cheating, boasting or behaving like an idiot, you’ll be flooded with invitations to appear on current affairs programmes. If you play straight, don’t expect the phone to ring.

In an age of 24-hour news, declining ratings and intense competition, the commodity in greatest demand is noise. Never mind the content, never mind the facts: all that now counts is impact. A loudmouthed buffoon, already the object of public outrage, is a far more bankable asset than someone who knows what they’re talking about. So the biggest platforms are populated by blusterers and braggarts. The media is the mirror in which we see ourselves. With every glance, our self-image subtly changes.

When the BBC launched its new Scotland channel recently, someone had the bright idea of asking Mark Meechan – who calls himself Count Dankula – to appear on two of its discussion programmes. His sole claim to fame is being fined for circulating a video showing how he had trained his girlfriend’s dog to raise its paw in a Nazi salute when he shouted: “Sieg heil!” and “Gas the Jews”. The episodes had to be ditched after a storm of complaints. This could be seen as an embarrassment for the BBC. Or it could be seen as a triumph, as the channel attracted massive publicity a few days after its launch.

The best thing to have happened to the career of William Sitwell, the then-editor of Waitrose magazine, was the scandal he caused when he sent a highly unprofessional, juvenile email to a freelance journalist, Selene Nelson, who was pitching an article on vegan food. “How about a series on killing vegans, one by one. Ways to trap them? How to interrogate them properly? Expose their hypocrisy? Force-feed them meat,” he asked her. He was obliged to resign. As a result of the furore, he was snapped up by the Telegraph as its new food critic, with a front-page launch and expensive publicity shoot.

Last June, the scandal merchant Isabel Oakeshott was exposed for withholding a cache of emails detailing Leave.EU co-founder Arron Banks’ multiple meetings with Russian officials, which might have been of interest to the Electoral Commission’s investigation into the financing of the Brexit campaign. During the following days she was invited on to Question Time and other outlets, platforms she used to extol the virtues of Brexit. By contrast, the journalist who exposed her, Carole Cadwalladr, has been largely frozen out by the BBC.

This is not the first time Oakeshott appears to have been rewarded for questionable behaviour. Following the outrage caused by her unevidenced (and almost certainly untrue) story that David Cameron put his penis in a dead pig’s mouth, Paul Dacre, the then editor of the Daily Mail, promoted her to political editor-at-large.

The Conservative MP Mark Francois became hot media property the moment he made a complete ass of himself on BBC News. He ripped up a letter from the German-born head of Airbus that warned about the consequences of Brexit, while announcing: “My father, Reginald Francois, was a D-Day veteran. He never submitted to bullying by any German, and neither will his son.” Now he’s all over the BBC.

In the US, the phenomenon is more advanced. G Gordon Liddy served 51 months in prison as a result of his role in the Watergate conspiracy, organising the burglary of the Democratic National committee headquarters. When he was released, he used his notoriety to launch a lucrative career. He became the host of a radio show syndicated to 160 stations, and a regular guest on current affairs programmes. Oliver North, who came to public attention for his leading role in the Iran-Contra scandal, also landed a syndicated radio programme, as well as a newspaper column, and was employed by Fox as a television show host and regular commentator. Similarly, Darren Grimes, in the UK, is widely known only for the £20,000 fine he received for his activities during the Brexit campaign. Now he’s being used by Sky as a pundit.

The most revolting bigots, such as Tucker Carlson and Donald Trump, built their public profiles on the media platforms they were given by attacking women, people of colour and vulnerable minorities. Trump leveraged his notoriety all the way to the White House. Boris Johnson is taking the same track, using carefully calibrated outrage to keep himself in the public eye.

On both sides of the Atlantic, the unscrupulous, duplicitous and preposterous are brought to the fore, as programme-makers seek to generate noise. Malicious clowns are invited to discuss issues of the utmost complexity. Ludicrous twerps are sought out and lionised. The BBC used its current affairs programmes to turn Nigel Farage and Jacob Rees-Mogg into reality TV stars, and now they have the nation in their hands.

My hope is that eventually the tide will turn. People will become so sick of the charlatans and exhibitionists who crowd the airwaves that the BBC and other media will be forced to reconsider. But while we wait for a resurgence of sense in public life, the buffoons who have become the voices of the nation drive us towards a no-deal Brexit and a host of other disasters.

• George Monbiot is a Guardian columnist