The Herefordshire legend of Black Vaughan tells the story of an evil 15th-century nobleman who returns in various spectral forms – a black fly, a black dog, a black bull, some gerbils – to molest farm girls, spill milk, and upset apple carts.

But the dead aristocratic pest is eventually subdued by 12 priests and a pregnant woman in the Welsh border town of Kington, in a priest/pregnancy-based variant on Kurosawa’s Seven Samurai. Folklore tells us that we too could defeat our current existential crisis, or Boris Piccaninny Watermelon Letterbox Johnson, as it is commonly known.

Despite initially supporting people’s right to wear the burqa, cake-and-eat-it style, Boris Piccaninny Watermelon Letterbox Johnson then ridiculed the ancient holy face window, simply to court the support of shy racists in his Gollum-like quest for the ring of power.

Boris Piccaninny Watermelon Letterbox Johnson was doing the same thing when he embraced the Brexit he never believed in, a lie built on bendy bananas, nonexistent NHS funding promises, and millions of imaginary migrating Turks coming over here, with their massages, their baths and their Delight.

Those in positions of power know what this incubus is doing, yet do not hold it to account

While there is a need for a robust debate on the role of religious symbolism in a pluralistic society, it is not clear if Boris Piccaninny Watermelon Letterbox Johnson is the most sensitive thinker we can throw at the issue. Especially when Boris Picaninny Watermelon Letterbox Johnson appears to be colluding with the white supremacist news-fabricator and former Trumpeteer Steve Bannon, who hopes to initiate a far-right rising across Europe while simultaneously wearing as many shirts as possible.

Boris Piccaninny Watermelon Letterbox Johnson is a fat naughty dog, running away from the butcher’s with a string of fascist sausages, made of all the least nourishing parts of already discredited arguments, chased by betrayed Leave voters in straw hats and blood-stained aprons, shaking their fists and waving their cleavers.

As my wife will happily tell you, barely a day goes by without my referencing the mythology of our isles to decode current events, and indeed I file this column from a campsite on the cliffs of Tintagel, deep in King Arthur’s Cornwall. My wife claims to be working all summer and I have taken the children, Gina (7) and Miller (11), away in a two-man pop-up tent, now strewn with filthy pasty wrappers, empty clotted-cream cartons, and unspooled Jethro tapes, pilfered from garage forecourt bins.

Sadly, the ease of modern communication means it has been impossible to escape from current affairs, even here, where news of Cornwall’s forthcoming post-Brexit collapse is finally making its way across the Tamar two years too late, borne by stumbling pack horses along EU-subsidised tracks.

Legend tells us that Arthur and his knights of the round table will rise from their Tintagel cave in a time of national need. But when Arthur wakes it will be too late, and he will emerge blinking into a swastika night of burning burqas and adequate food, cursing his cockerel, and blaming a bad pint.

Look instead for a solution to the Boris Piccaninny Watermelon Letterbox Johnson problem in the tale of Black Vaughan. According to Frederick Grice’s 1952 study, Folk Tales of the West Midlands, it was a wise man from the Welsh Marches who told the people of Kington to fill St Mary’s Church with 12 stout clerics and a pregnant woman, the latter to tempt Black Vaughn, in a strange half echo of Boris Piccaninny Watermelon Letterbox Johnson’s own reckless proclivities.

Sure enough the chaotic spirit, a slippery devil that evaded capture by conventional means, soon entered the midnight church. But each time one of the clerics actually stood up to Black Vaughan’s verbal provocations, the demon shrank a little in size, until he was finally trapped in a snuff box and thrown into the deep lake at nearby Hergest Court, where he remains to this day.

Stand up similarly to Boris Piccaninny Watermelon Letterbox Johnson’s bullshit and he too will shrink to snuff box size. But who will defy him? The collaborators of the Today programme genuflect giggling before him; the Daily Telegraph, Britain’s worst newspaper, funds his blatant falsehoods and algorithmically generated controversies to drive web traffic through its collapsing gates; the Have I Got News For You team, who taught Boris Piccaninny Watermelon Letterbox Johnson the skills he now uses to court the very worst people on Earth, hand their single tooth along their panel show desk powerlessly; Theresa May cowers in impotence like King Théoden, as Jacob Rees-Mogg’s Hard Brexit Uruk-hai approach the citadel; and news folk are wafted away with a tea tray.

Those in positions of power – journalists, fellow Conservative party members wondering how things will pan out, people biding their time on the divided opposition benches, trembling television presenters in search of “balanced arguments” in the face of blatant lies and transparent manipulation – know what this incubus is and what it is doing, and how it is prepared to put our futures at risk to achieve it. And yet they do not hold Boris Piccaninny Watermelon Letterbox Johnson to account. They will not shrink Boris Piccaninny Watermelon Letterbox Johnson to snuff box size and sink him into the black lake of legend where he belongs. They will have to live with their failure. And, sadly, so will we.

Twelve wise priests and a pregnant woman cast Black Vaughan out of Kington church and into the deep water. But, to be fair, what if the devil man Black Vaughan had his own funny weekly newspaper column? What if, instead of looking like a giant fly or a bull, he had amusing floppy hair, messed up to order? And what if, instead of swooping about like a frightening spectre, he had a tray of tea at the ready to catch his opponents off guard? No one could realistically be expected to stand up to such powerful strategies.

Stewart Lee’s Content Provider tour show is available on the BBC iPlayer.