To the GBP2.9m Downing Street briefing room, and a Monday matinee performance by dissolute children’s entertainer Boris Johnson. Johnson always looks nervous talking to kids, as though he’s afraid one of them might ask for a hair sample or his discarded coffee cup. Still, here he is, Climate Santa – holding a Q&A with some youngsters in a show that never felt more than four seconds away from a slurred, “I’m sorry kids, I just threw up a little in my prime minister’s costume.”

We already know that many children live with a sense of powerless anxiety about the climate crisis – and these ones had presumably been handpicked for being particularly committed to the cause. So really, just a very special outreach effort from the PM. Let’s take a look at some of the lowlights. “Recycling isn’t the answer, I’ve got to be honest with you,” the prime minister told their little faces, as the WWF UK chief executive next to him suppressed another thousand-yard stare. “You’re not going to like this. It doesn’t begin to address the problem”; “We need to have municipal toothpaste, something or other, we’ll work this out later”; “We have to encourage [cows] to stop burping”; “It’s going to be very, very tough, this summit, and I’m very worried because it might go wrong. We might not get the agreements that we need. It’s touch and go, it’s very, very difficult … It’s very far from clear that we’ll get the progress that we need.”

How – HOW? – did some grim-faced aide not burst through the doors and wrap it up. “OK kids, Climate Santa’s feeling tired now, so if you could just find your way back to your parents that’d be great. Don’t forget to sign the safeguarding waiver; and if you post about this on Tripadvisor you’ll receive a lifetime store ban. Oh stop CRYING, you little squits – you got to see the briefing room didn’t you?”

Britain: a country hosting a climate summit next week. Also: a country where the governing party just voted to allow water firms to keep discharging raw sewage into the nation’s rivers and seas, a practice they indulged in just the 400,000 times last year. Time to add irony to the extinction watchlist. During the G7 meeting at Carbis Bay last summer, the prime minister took a swim in the Cornish sea. I wonder if next week in Glasgow he’ll take a dip in the Clyde, into which Scottish Water have released hundreds of millions of litres of raw sewage. Finally, a wild swimming article I’d actually like to read.

The PM has yet to give us his Rivers of Crud speech, but no doubt it’s in the post. In many ways, sewers are his natural territory. Students of Johnsonlore will know his prime ministerial origin story is akin to one of those urban alligator myths. In the immediate aftermath of the 2016 referendum, Johnson was flushed down a toilet by Michael Gove. But instead of ridding us of an unwanted pet, this allowed Johnson to bide his time in the sewers. Thence emerged a vast mutant Johnson, which now stalks our politics, devouring all before it.

Even so, this current sewage-dumping story feels unfortunate. There is something Swiftian about the rising tide of effluent passing from the metaphorical to the literal. Johnson’s Brexit deal has disrupted imports of water treatment chemicals – another deeply foreseeable and indeed foreseen consequence for which this faux environmentalist failed to plan. It is, however, fair to say that better outcomes were available. As Conservative backbencher Steve Double once intoned in a 2019 Commons debate over Theresa May’s deal: “This is a turd of a deal, 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.”

Well quite. I note that despite having previously allied with Surfers Against Sewage and chaired something called the Protect Our Waves group, Mr Double is one of those MPs who held his nose and voted for water companies to be allowed to continue dumping sewage. Since we’re in the Swift section, here are some of the poet’s thoughts on the Irish parliament of his day: “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”

Of course, this isn’t quite how MPs see it, with reactions to the public drubbing they’re receiving on this issue ranging from indignation to suggestions that it’s bullying/hate speech. Apparently, they’ve only done what they’ve done to protect bill-payers from having improvement costs for chronically under-invested sewerage infrastructure passed on to them.

This feels somewhat confusing. After all, water privatisation was originally pushed as the best way of getting investment ploughed into the infrastructure. It’s almost as if those water firms have instead ploughed GBP57bn cash into their shareholders, leaving them with no choice but to spray sewage into rivers every time it rains a bit. Also left with no choice are some of our aforementioned Conservative MPs, who have responded to public outrage by writing pissy little blogs about how they’re only voting in favour of it to help consumers with their bills. To which one response might be: maybe stop “helping” consumers? It’s almost as if you’ve spent the past few decades “helping” consumers to line the pockets of profiteers. Every time you try to “help” consumers, another few million litres of sewage gets flushed into places they love and value.

Still, what a backdrop for Cop26, already shaping up to be the opposite of Sleeping Beauty’s christening. Which is to say, none of the bad fairies actually want to come. Earlier this month, it was Chinese leader Xi Jinping’s turn to find himself otherwise engaged. Latest to phone in with an excuse is Vladimir Putin. I haven’t treated myself to yesterday’s No 10-issued readout of Johnson’s call with the Russian president. But I imagine it went along the lines of, “Sorry mate – I’ve tested positive for not giving a litre of sewage about your climate event.”

Small wonder, perhaps, that Johnson is already retreating into his briefing room, which was famously not even single-use and looks extremely plastic. It’s too soon to definitively conclude the PM’s Cop26 preparations have been so half-arsed as to be a Cop Out. But if he wants to get out of Shit Creek, he’s going to need a bigger paddle.

• Marina Hyde is a Guardian columnist