What does a stream of raw sewage symbolise? Broken Brexit promises, for one

I remember the good ol’ days, when we weren’t always lurching from one crisis to another and we had time to wonder why the EU’s clean-beach legislation hadn’t done more for its popularity. Maybe people just didn’t care about sewage, one way or the other?

That was possibly the working assumption of Conservative MPs, who are now experiencing mounting unease – lobby-speak for freaking the hell out – over the environment bill that is ping-ponging through parliament. It’s a rangy piece of legislation, of which the faeces element is only a small part. A Lords amendment sought to put a duty on water companies not to dump raw sewage into the waterways – and 265 Tories voted against it. The website Evolve Politics published the list in full and thus crashed itself, so urgent was public interest in the names. Querulous Tories are taking to Twitter crying fake news, puzzled by the strength of public feeling.

I think I can help, here, with a little explainer. Sewage has become a powerful symbol of a number of things at once. First, all those Brexit promises – that nothing would change, except to improve; that our environmental protections without the EU would be, if anything, better. The boot is on the other foot in this rift that won’t heal – it used to be remainers making detailed, boring, practical arguments, while Brexiters sang their full-throated freedom shanties. Now, it’s leavers trying to make the case for complexity – “We think you’ll find this is actually about heavy rainfall and Victorian sewerage” – while remainers are making the simple, emotional case: “Things used to be better and now they’re shit.”

Second, running up to Cop26, there is a building sense that the environment will bear the brunt as we witness the consequences of electing a joke government that doesn’t keep promises.

Third, the downsides of privatisation are often palpable but opaque, hard to prove and speculative. Not in this case. Water companies pump out raw sewage because they can’t afford the infrastructure improvements it would take not to do so; they have also paid out £57bn in dividends over the past 30 years. If there is one thing worse than an issue that distills several cases at once, it’s one of which the metaphorical potential is so rich that it would be vulgar to mine it.

• Zoe Williams is a Guardian columnist