How The Mezzotint changes the original MR James short story

"There’s such a joy in making another adaptation. I love James, obviously. MR James has an immediate impact when [people] see the name. They get it. And there’s such a lovely, honourable tradition. There’s lots of his I’d still like to do."

This time, he’s recreated one of James’ best-known but least-adapted ghost stories, the Mezzotint – and recreation might be the best word for it, with the plot, setting, characters and even dialogue closely matching what’s on the page.

"It’s a funny process, really," Gatiss told us. "For instance, obviously Steven [Moffat] and I have quite a reputation for tackling famous things head on, and being liberal with them. But at the root of it, there’s always the same thing, which is actually a great respect for the original.

"I’m doing it with A Christmas Carol, which I’m doing on stage at the moment. It’s extremely faithful – actually, weirdly, because it rarely is. Sometimes the most radical thing to do is to go back to the book, and do lots of things which are rarely done. Obviously, Dickens was a genius. James was a genius."

In the short story, and this TV version, a blithe academic called Williams (Rory Kinnear) is sent a mezzotint (i.e. an engraving taken from a copper or steel plate) of a fairly ordinary looking country mansion. However, over the course of several days the picture begins to change, first in minor ways (moonlight and so on) and then more severely as a ghastly, spectral figure lurches up the lawn, disappears inside the house and exits carrying a baby.

As noted, the TV adaptation follows this fairly closely – some dialogue is lifted right from the page – and while one or two characters are slightly changed or gender swapped, they retain their role in the story.

Where Gatiss does go a little more off-piste is in the ending, which he completely changes from the text. So why be so exact in one moment, and add so much the next?

"You know, I think what you usually end up doing with an adaptation, say, of an MR James story, is trying to preserve the stuff that works best as dialogue, and isn’t too chewy, but still has a wonderful period flavour, and then expanding the parts which need expanding," he explained. "The whole of the ending is new, really, because in the story it sort of just peters out.

"But that’s perfectly right and legitimate. It’s an adaptation. Jonathan Miller said, right back at the beginning, about… he was actually talking about his Alice in Wonderland adaptation, but equally his [MR James adaptation] Whistle and I’ll Come to You, that if you’re just going to do it, you might as well read the book, or read the story."

In James’ version of the story, Williams and his colleagues discover the mezzotint depicts a long-ago tragedy where a wealthy landowner had a poacher hanged, only for the poacher to (apparently) rise from the grave, creep into the house and steal the young heir.

Gatiss’ innovation is to tie Williams closely to this backstory – as it turns out, he’s descended from the Francis line himself (presumably, this is how the supernatural picture found its way to him), and may be marked for death as well. Williams destroys the Mezzotint, but some time later finds a new one of his own window, with that same figure crawling up the grass towards him.

"You know, it’s like any adaptation," Gatiss said. "There’s a reason people often say that short stories make better movies than novels do, because, actually, you’ve got more room to make them breathe, and you’re not religiously trying to photograph every scene from a novel or something like that.

"And also, it’s a different form. You’ve got to feel like you could adapt it, and invent, and make it suit, you know, film or television in that way. Otherwise, it’s just a sort of static retelling of it."

Somehow, with the Mezzotint, Gatiss has achieved the best of both worlds – a faithful retelling with a real sting in the tail. You may never turn your back on a painting or engraving ever again…

The Mezzotint is now available on BBC iPlayer – for more, check out our dedicated Fantasy page or our full TV Guide.