As a small child, I was always being told that I was sensitive. This was a bad thing, I understood: akin to being imaginative, or even worse, peculiar. I lived in a dream world of my own; had invisible friends; lay awake at night half-paralysed by the inevitability of death. I spoke more readily with adults than to my peers, who seemed to me an entirely different species. Throughout my first term at infant school I pretended I was a dog, in the mistaken hope that this would make other children like me. If I’d been born a generation later I might have been labelled autistic. As it was, people thought I was weird; teachers as well as pupils. I didn’t feel weird; but I was aware of somehow feeling differently.  Much later, I discovered that I had a form of synaesthesia, a neurological condition which in my case means that colours trigger associated scents (blue, coconut; red, chocolate; purple, patchouli). In practical terms, it means that I tend to notice colours and scents before I notice anything else, which may be why they play such an important part in my books. But we all have a dominant sense through which we approach and process the world, just as none of us can be entirely sure of how other people experience reality.

In another life, I was a teacher of French in a boys’ school. In an attempt to help the boys remember lists of vocabulary, and knowing that most people have a visual memory, I encouraged them to list masculine words in blue, feminine words in red. About half of the boys in my class saw an immediate improvement in their recall of the words. But what about the others? Not everyone has a visual memory. And so I recorded lists of French words for those with an auditory memory: I introduced a series of tapping movements for those with a kinetic memory. Eventually, every boy in my class had a method that worked for him. Later, in my writing career, I remembered this experiment, and promised myself to include all the senses in my writing, so as to ensure as immersive an experience as possible for my readers.

We all process reality via our senses. We are all sensitive to different things.  This is true of fiction, too; our imaginations are all unique, as is our ability to process fiction. All my books have come to me primarily from the senses. First comes scent, which I often use as a creative trigger (Stanislavski suggests this in An Actor Prepares as a means of getting into character; I find that it works just as well as an author, creating characters). And scent is often so closely linked to memory and emotion that it can trigger intensely personal responses. Next for me is colour, so closely linked with scent because of my peculiar neurology. Bright colours not only smell wonderful, they deliver an instant shot of dopamine. And taste is closely linked with scent, with all its associations. Then there’s the sound, the music of words, and how reading aloud brings the page to life: that’s why reading my work aloud has become such a part of my process. And the physical ritual of walking the hundred yards to my shed, sitting at my desk, making a cup of tea, touching the objects I like to keep by my side when I am writing (a beach stone from Noirmoutier, a little brass frog from my grandfather’s  study) all this adds to the process. Every book starts with a scent, a sound, a colour, a walk and of course, that vital cup of tea; a morning ritual that dates all the way back to my teaching days, with all its particular memories. Senses are life; they are joyous; and although we all feel them differently, they are part of what connects us.

That’s why I found writing Sleepers in the Snow such a disquieting experience. It’s about the absence of senses; the loss of connection, the erasure of memory. It’s a book in which familiar things vanish without explanation; where daily walks become perilous; where scent heralds a haunting; where nothing, not even memory, can be entirely trusted. Even the winter landscape disappears under a covering of snow. There are no colours, no scents; no sounds. The sky is a field of white noise. To me, this is the definition of fear: the absence of physical touchstones; the slipping into oblivion. Every horror novel at heart is really about the fear of death; and Sleepers is no exception. It’s a quiet study of fear, in which all the monsters are human, and where nothing – not even the senses – are real. Some novels of fear are labelled as being not for the sensitive; but this was written especially for those who feel a little too much; for those who see faces in the clouds and lie awake on winter nights.

Where did the story come from? Well, as always, it starts with the senses. The scent I used was a fragrance from 4160 Tuesdays called The Lion Cupboard, which to me is the scent of a haunted wardrobe, filled with the slightly moth-eaten clothes of another century. I used it to enter the haunted world of Sleepers much as the Pevensie children found their way into Narnia. My walk to the shed was often through snow – I wrote this book over a single winter – and its soundtrack was the crunching sound of my boots over the frozen ground, and the call of jackdaws and crows, and the whish of the wind through the leafless trees. Its colours are almost monochrome; the greys and browns and chilly off-whites of the winter landscape. And at the emotional heart of all of it lies the death of my father; his dementia: his spiral into silence; his small and valiant attempts to defy the inevitable.

I think it’s a quietly frightening book. But it’s also a cathartic book; a story of confrontation in which our darkest fears take shape. And although it’s a story of loss, and grief, and the vanishing of the senses, I think it’s as fully immersive as any of my other books. Read it with a cup of tea; a blanket; a candle to banish the ghosts; and make sure all the doors are locked; and the windows are shuttered against the night.