“It … sends a message … to the whole world,” croaked Theresa May to the Commons on Tuesday night, “about the sort of country … the United Kingdom will be … in the years and decades ahead.”

Fairly sure the world has got the message by now. They are “up to speed” and “across the detail” of the sort of country the UK is. The question of whether Brexit represented a midlife crisis or the descent into senility appears to have been answered. The land that likes to picture itself as a David Niven world war two movie is in fact a look-away episode of The Jeremy Kyle Show. On close inspection, the “beacon of democracy” turns out to be a bin fire.

By now, you will be aware that the prime minister failed to end her meaningful vote hoodoo, with this sequel to her last attempt – 2Meaningful 2Vote – knocked down by a margin of 149. Amusingly, some are suggesting that Meaningful Vote: Tokyo Drift could yet happen. A free vote on no deal takes place tonight, with potential amendments piling up. May herself ploughs on. It’s as if someone has popped a grey wig on Munch’s The Scream, then cast it in an ITV drama about the female governor of a category-A prison.

Quote of the debate – arguably quote of the entire Brexit – went to a Conservative backbencher by the name of Steve Double. “This is a turd of a deal,” he intoned to the House of Commons, “which has now been taken away and polished, and is now a polished turd. But it might be the best turd that we’ve got.”

For many, the now-reflexive action when they hear this kind of stuff is to inquire “why didn’t u put that on the side of ur bus m8???”. And yet, was Steve’s interjection in the actual chamber the moment that well-worn joke format ascended to its purest – which is to say, its most grotesque – form? Putting turd all over the side of a bus, having half the country vote for it, and then driving this dirty-protest-mobile past every single warning-sign of the past two and a half years has brought us to this particular precipice. Tuesday night’s Commons spectacle reminded me of one of Jonathan Swift’s last poems, about the Irish parliament – specifically this bit:

“Let them, when they once get in,

Sell the nation for a pin;

While they sit a-picking straws,

Let them rave at making laws;

While they never hold their tongue,

Let them dabble in their dung …

We may, while they strain their throats

Wipe our arses with their votes.”

So yup, pretty much all covered by Dean Swift there back in the 1730s, right down to Theresa May’s strained throat. However unique this moment might feel, I suppose we must remember that politicians have been letting down their people for centuries and centuries.

Even so, the abysmal calibre of those in whose hands we’re in can feel remarkable. Nigel Dodds! Have you beheld Nigel? If you didn’t know he was the deputy leader of the DUP, you’d say he has the face of a head of geography who has been suspended pending an investigation into accusations he struck a pupil. Or perhaps you prefer Boris Johnson, who stood up to urge to parliament to “behave as a great country”. Says the guy who’s been behaving like a complete country since prep school. According to that guy, no deal is “the only safe path to self–respect”. Boris Johnson showing you the only safe path to self-respect is like Paul Burrell showing you the only safe path to dignity, or Hannibal Lecter showing you the only safe path home. With his elite-busting reference to “Carthaginian terms”, Boris is entirely of a piece with Jacob Rees-Mogg, who on Tuesday tweeted simply: “Dies irae, dies illa”. To read fan replies humbly begging “give us a clue Jacob!” (in vain) is to be reminded that all populists secretly hate their people; but these two do it openly.

‘Corbyn now seems to be back to pushing his phantom Brexit deal, as opposed to the second referendum he briefly suggested was Labour policy.’ Photograph: Luke Dray/Getty Images

Fans of sledgehammer imagery, meanwhile, may care to note that disgraced former Conservative politician Jeffrey Archer was sitting in the public gallery on Tuesday night, while disgraced former Labour member Fiona Onasanya became the first MP to vote while wearing an electronic tag. Four decades of gathering uselessness and mendacity had brought us to this occasion, to which we might as well picture Archer and Onasanya as bookends.

If it feels unfair to lump most of the House of Commons in together, please don’t let it. It must not be forgotten that MPs voted 498 to 114 to trigger article 50 two years ago, apparently without a clue what the predictable implications of negotiating against the clock with a much stronger opponent were. Most of those 498 MPs are a reminder than no one in this country should ever suffer from impostor syndrome again. I really do hope to see as many of them as possible at the eventual public inquiry.

The story of Brexit since the referendum has in large part been the story of politicians finding out in real time what the thing they had already done actually meant, then deferring the admission or even acceptance of it. We hear a lot about low-information voters, but low-information politicians are the bigger problem. Even this week, Tory Brexiteers Esther McVey and Daniel Kawczynski were spreading arrant lies about enforced joining of the euro. It is traditional at these moments to ask if the politicians in question are stupid or liars; in the case of Esther and Daniel, the question is moot as they are both.

Westminster has become so unmoored from reality that half of its denizens can’t even remember which lie they told. In the wake of May’s defeat, Tory deputy chairman James Cleverly informed the BBC that she had “inherited this job”, like it was some loss-making family business May had sportingly tried to make a go of, as opposed to the position of prime minister, which she’d remorselessly pursued, to the point of having been too self-interested to even fight for her side in the referendum.

On the other side of the house, meanwhile, sat Jeremy Corbyn, who famously wanted to trigger article 50 before anyone else, on the very day after the referendum. Yet on Tuesday he was wittering at the prime minister: “The clock has been run out on her!” Corbyn now seems to be back to pushing his phantom Brexit deal, as opposed to the second referendum he briefly suggested was Labour policy. I know rebelling against the leadership is Corbyn’s comfort zone, but it does make you look a historic tit when you are the leadership.

As for what happens next, one Tory MP judged: “Fuck knows”. Welcome to Fuckknowsville. Population: us. In Westminster, an MP leaving the ERG meeting had called the mood “realistic” before adding: “but the question is, what is reality?” No. The question is, what is this complete bollocks? Morpheus, but if he was the member for Wycombe? In the north, Nigel Farage’s Leave Means Leave army girds itself to march south from Sunderland to London. And in Brussels, one EU diplomat warned ominously that “behind the scenes people are increasingly saying it is better to call it quits”, which is diplomatic speak for “so completely done with the UK’s shit”.

We might as well play out with former Brexit secretary David Davis, whose appearance before the eventual inquiry will, I fantasise, be lengthy and sensationally uncomfortable. “If we walk away,” David breezed breezily on Tuesday, shortly before U-turning and voting for a deal he had spent months pissing all over, “What can they do? They cannot invade you, can they?” More’s the pity. If only there was an option for “invasion by competent people”. They don’t have to be FROM the continent, but they do have to BE continent.

• Marina Hyde is a Guardian columnist