Have you ever looked into the eyes of a hedgehog and known that it wanted to die? I have. But wait, I am getting ahead of myself.

On Halloween, as we headed west in our Volkswagen Passat, I realised the most horrifying thing in the vicinity was our own family estate. With our car belching toxic death, courtesy of a secret cabal of heartless engineers hellbent on the end of humanity and the ecosystem as a whole, I joked to my wife, “Next Halloween I’m going dressed as a Volkswagen!” “You should,” she replied, stony-faced and expressionless, like a cement yak, “and you certainly wouldn’t have any trouble providing the noxious emissions.”

(This may seem like amusing marital banter to you, but my wife knows full well that I have had a long history of painful bowel problems, beginning with an unexpected bout of ulcerative colitis as a teenager, and culminating in hospitalisation as a result of diverticulitis in my late 30s, a condition which still requires careful daily management and, admittedly, can lead to occasional and unpleasant flatulence. I include her supposedly amusing comment here only to bolster the legal dossier I am preparing in advance of our divorce.)

I think it was the TV fisherman Robson Green who said, ‘You cannot step twice into the same river’

When I was a child in the 1970s, my mother would take me out into deepest rural Worcestershire, on the Saturday before 5 November every year, to see the ageless traditional celebrations in the tiny village of Monk’s Norton. We stayed each year with the elderly Dr Hemming, for whom she had worked as a medical receptionist in Birmingham, before he retired in the mid-60s after a scandal involving a missing carton of Drinamyl, some ancient manuscripts, a replacement aortic valve, and a dead weasel.

“How nice to see you again, Dr Hemming,” I would say politely, as my mother had rehearsed me in the Hillman Imp, “I hope you have had a pleasant year.” “Years are meaningless, boy,” he would reply, vaguely, “Time is an illusion. Flesh is a gossamer shroud. One day I will take on any body I choose. Would you like some hot eels?” I always enjoyed our visits.

As the flames flickered outside his window, Dr Hemming would stare at them in a thaumaturgic trance through a haze of self-prescribed temazepam and hand-pulled Watney’s Party Seven, and my mother and I would head out into the famished night to seek out the ancient pagan England of our collective northern European subconscious, and some sausage. You have not known sausage until you have known it while watching an effigy of Joe Gormley burning on a bonfire in 1975 in a solidly Conservative-voting Worcestershire village.

While I applaud how the American tradition of trick or treat has taken off in my London neighbourhood, I worry it has made Halloween too commercial. This year our neighbours were ritually intimidated by resentful children dressed respectively as Siri, the Playboy Bunny logo, and an Amazon Fire TV Stick. Another satirically minded youngster appeared inside the severed head of a pig with a Conservative party rosette pinned to its face, which I thought inappropriate, as we live in an orthodox Jewish area.

But I wanted my own children to enjoy the same festivities that I experienced as a child, and so it was we loaded up the Deathwagon last Saturday morning and headed to Monk’s Norton. The hamlet was hemmed in now by the heavy traffic of the M5 and the M50, and smells more of fuel than it did 40 years ago, but is still identifiably itself. Dr Hemming was long dead, I expect, but as we drove at dusk down the leafy lane past the vicarage where the obtuse physician had lived, I saw a small white-faced boy staring all-knowingly from the window, as if heavy with the apprehension of eternity, and then withdraw.

I think it was the TV fisherman Robson Green who said, “You cannot step twice into the same river.” I had perhaps been foolish to expect the Monk’s Norton festivities to have remained unchanged. In the 70s, each year an effigy of a trade unionist burned on the pyre – Jack Jones, Derek Robinson, Len McCluskey, Mick McGahey – but now even in relatively homogenous rural Worcestershire, Britain was clearly divided in who it chose to demonise.

Upon the village green, by torchlight, in the flickering shadows of the tall Tudor houses, rival factions squabbled, dragging different effigies towards the unlit bonfire. Here was Jeremy Clarkson, innocently piling his fist into a selfish minion’s face; and here was a selfish minion, stupidly allowing his face to connect with Jeremy Clarkson’s fist, denying us future Top Gear; and here was David Cameron, in farm girl’s frock and bonnet, borne aloft in plywood pigsty, fair Chloris, innocent and pleased; and here, a papier mache Martin Winterkorn, head of Volkswagen, strangling the green earth with his clean hands. And so on, and so on, a multitude of villains and no clear candidate for the conflagration.

And then a shrill voice cut through the commotion: “Burn them all.” It was the little boy from the window, in pantaloons and waistcoat, with a cold authority beyond his years. As the people of Monk’s Norton surrounded the bonfire, hurling their hated effigies onto it, I was sure I saw him crawl between their legs and into the pyre. Before the head of the Round Table, dressed amusingly as a sponging Pacific Islander displaced by rising sea levels, could light it, I persuaded him to let me crawl inside. The boy was not there. But a hedgehog was. I recognised the look in its eyes. It knew its time was up.

When I was a child, there were 30 million hedgehogs in the UK. We were cavalier about their abundance, and their tyre-squashed early morning bodies were so commonplace it seemed they must be in almost endless supply. Now – because of climate change and the collapse of their food chain – there are less than a million. We can’t even save the hedgehog. How do we expect to save the world?

Last month, we imagined there was a hedgehog in our garden, by virtue of a telltale track, and we invested in hedgehog food from an online outlet. But it has proved to be a phantom hedgehog, and our nightly replenishment of the illusory hedgehog’s saucer was an act of delusional wish-fulfillment. I think the cat ate the hedgehog food. That would explain why he has developed bristles and a taste for worms. There should have been a warning on the box. I think so anyway.

A Room With a Stew is at Leicester Square theatre, London WC2 until 8 Jan. Stewart Lee is the curator of next year’s All Tomorrow’s Parties festival, at Prestatyn Pontins, 15-17 April 2016