In the late 70s and early 80s Jan Mark published a trilogy of what I called ‘metaphysical thrillers’: The Ennead, Divide and Rule and Aquarius. These were challenging reads that could just as easily have been published on an adult list. In 1988 she published an adult novel, Zeno Was Here, in which one of the main characters is casually killed off half-way through the story, not for any reason of plot, but because these things happen in life.

This callousness towards her creations, the ‘splinter of ice’ that Graham Greene said lurked in the heart of every writer, was already evident in her chilling sort story ‘Childermas’, a haunting tale of horror and revulsion. It was included in Two Stories by Jan Mark, in a limited edition of 225 copies published in 1984 by Dennis Hall’s Inky Parrot Press; the second story was a suburban psychodrama enacted by a pair of dolls, ‘Mr and Mrs Johnson’.

When I interviewed her in 1983, Jan told me, ‘I want to do an adult novel. I mean one that can’t possibly be published as a children’s novel.’ For a while, she thought that ‘Childermas’ might be the beginnings of that. I met her at some do sometime around 1985, and when I mentioned how much I liked the story, she told me she was thinking of expanding it into a novel. Her face fell when I told her that Wyndham Lewis had already published a novel called Childermass.

I think it would have been difficult in any case to expand ‘Childermas’, because as is the way with perfect things, if you started tinkering with it you would risk damaging it beyond repair.

It starts in a primary school classroom, in which the teacher, Mr Oliver, asks the class, ‘Do you believe in fairies?’ It could be the beginning of a children’s story. But it is not, it is the beginning of a journey into darkness and disgust.

For Mr Oliver has found fairies at the bottom of his garden, and they are not the charming Edwardian fairies dismissed by Kipling’s Puck as ‘that painty-winged, wand-waving, sugar-and-shake-your-head set of impostors.’ In fact, ‘He had thought at first that they were maggots.’

‘It was the writhing that had made him think of maggots, but what he had initially taken for one was in truth two, clamped face to face together and disinterestedly coupling.’

He uses the leisure of the weekend to investigate these strange, repellent creatures. Leaning over their burrow in the dawn light, he hears ‘not the shrill twittering of popular imagination, but the low amphibious gutterals of minute cleft palates.’

He starts out making a ‘scupulous excavation’ in the spirit of scientific enquiry, although with makeshift tools found in the kitchen: ‘Punctiliously he sorted through it all with Amanda’s eyebrow tweezers, separating it, animal from vegetable, into the two pâté bowls.’

Examining the mummified corpse of one of these painfully degenerated fairies, he finds that, ‘On either side the deviantly curving spine the shoulder blades rose in sharp crests, the scapular cavity of each veiled by the parchment fronds of ragged vestigial wings.’

Now, ‘He wanted to examine a live one.’

This is where the tale, already full of Oliver’s sense of revulsion and disgust, takes the dark turn into horror. He destroys the burrow, and watches the creatures pour out ‘in a torpid surge … croaking distressfully.’ One of them, more agile than the rest, climbs up inside his trouser leg, and he flings it into the ditch. The others take cover, but he picks up the braver one.

‘Instantly he felt the whirring of an overtaxed heart beneath the cushion of his thumb. The limbs flexed in spasms and the head rolled back dangling, and it died. A drop of expelled liquid spilled across his palm.’

The episode leaves him ‘weeping with repugnance and shock.’ He is so distressed that he does not dissect the corpse, as he intended, but flushes it down the lavatory.

He ponders if he can capture the whole tribe, and keep them in a glass vivarium. But he knows they should be left in their natural habitat, ‘to spawn horribly under the hedge.’

He remembers the contrasting romance of ‘Midir’s Song’ by Fiona Macleod, ‘They have faces like flowers, and their breath is a wind, blowing over summer meadows, filled with dewy clover.’

At two in the morning, he wakes and feels something moving across his thigh. ‘It was a female this time. In the light of the bedside lamp he saw her creeping mazily through the hair of his groin, nostrils fluttering in confused response to a discerned odour.’ Abandoning his conservationist pretence, he sweeps her off, breaking her neck, and smashing her into the wall where she ‘fell like a singed moth to the carpet.’

It is only then, ‘shivering with fear and remorse’, that he notices the trail of small red marks leading up his inside leg.

In the morning, he goes out to the burrow with an axe and a heavy shovel, ‘and smashed and smashed and smashed.’

On Monday afternoon we are back in class. Mr Oliver is grey round the mouth and unwell, and he has a temperature, and ‘the little sores on his leg were festering’.

Kind-hearted Cathy, one of his pupils, approaches him with a drawing. ‘“Look, Sir,” Cathy said, “I drawn you a fairy.”

‘He stared incredulously at her sprawling portrait; the face with both eyes on one side of the head, the long arm and the short, the fat leg and the thin, the unequally fingered hands and toeless feet, and spread anamorphic torso: a very accurate representation he thought, as the lights went out, the ceiling tilted askew and Cathy’s surprised face slewed away from him, of what must now lie under the hedge at the bottom of the garden.’

Childermas or Childermass is the Feast of the Holy Innocents. In this extraordinary and chilling short story, Jan Mark invokes the sheer horror of a holocaust, the extinction, we must assume, of the last spavined survivors of a once-proud race. In the course of enacting this genocide Mr Oliver has also sealed his own doom; we do not expect him to survive those festering sores.

I am not a great reader or admirer of horror stories, but this one gripped me when I first read it 35 years ago, and still grips me today. It’s a reminder of what a wide range Jan Mark had as a writer, and how surefooted she was in finding the right register and the right vocabulary for the right story.

Further reading: Don’t miss Neil Philip’s interview with Jan Mark.