TV: Agatha Christie adaptation stirs up a witch’s brew of woe

Five years on and the screenwriter's annual novel-to-screen reworkings have become a serial staple in the BBC One schedule, with her repertoire spanning from And Then There Were None to The Witness For the Prosecution, Ordeal by Innocence, The ABC Murders and now The Pale Horse.

"I didn't know it was going to grow into a quintet!" she quips at the premiere of the latter.

"The idea came to me when I was doing And Then There Were None, that maybe there would be a way to tell a story about 50 years of a blood-soaked and tumultuous 20th century via the medium of murder mystery - from a writer who maybe didn't invent it but certainly made the genre her own!

"Christie had such a long writing career, pretty much from the early Twenties until the Sixties - that's a long time to be writing and observing," she goes on. "So there were a few titles we could have thought about [for the later part], but then you've got this story, [The Pale Horse]...

"There's the opportunity to be in 1961 [London] with all the technology, there's the trial of Eichmann in Jerusalem, the Berlin Wall going up; and in a deep green wrinkle of the English countryside you have three witches... I mean, how could you not? It's a red rag to a bull!"

So what else do we need to know about the upcoming drama?

WHAT'S IT ABOUT?

The Pale Horse - the first of Phelps' adaptations to break the habit of airing over the festive season - puts Emmy and Bafta-nominated Rufus Sewell in the lead role of Mark Easterbrook, a man who seemingly has it all: he's rich, successful and popular, with a beautiful new wife (Kaya Scodelario) and perfect home.

But scratch beneath the surface and Easterbrook - still grief stricken by the loss of his first wife - soon finds his life turned upside down when his name appears on a mysterious list found inside the shoe of a dead woman.

His pursuit to find out leads him back to the village of Much Deeping; an idyllic English village, but also a place of old tradition, strange beliefs, three suspect witches, curses and spells.

With rumours that the trio of witches (played by Rita Tushingham, Sheila Atim and Kathy Kiera Clarke) played a part in the death, and with the body count continuing to rise, Easterbrook becomes hell-bent on finding an explanation, eventually fearing for his own life and sanity.

TAKING THE LEAD

For Sewell, 52, the two-parter marks his first foray into the twisty world of Christie.

"It was an instant yes!" recalls The Marvelous Mrs Maisel actor, who co-stars alongside Bertie Carvel, Sean Pertwee, and Henry Lloyd-Hughes, among others. "I've always wanted to do an Agatha Christie because I've grown up watching them - but this is so different to that, this is not cosy at all!"

As for Mark: "It's limited what I can say, but yes, [he's] quite a complex character," he adds. "He's superficially quite fun for me to play because I like the idea of the suits and the cars... But what's interesting for me in a deeper way is psychologically he's complex and challenging.

"That's the whole point of the car, the women, the suits, the hair and the cuff links; it's all an effort because there is a malignancy," he warns.

"There's something about the exteriors of these people, that in order to support that level of luxury there's an underbelly of brutality to maintain it, in society," he follows. "That seemed to be really reflected in this particular character's story, and I think it runs through Agatha Christie."

DELVING DEEPER

It's about lies, paranoia and conspiracy, reasons Phelps: "That no matter how rational and tough you think your resilience is to whispers and the little sharp fingernails scratching the back of your neck, you fall prey to it.

"We're all rational when the lights are on; and where we are at the moment, with the amount of disinformation, how do you hang on to what's true and decent without descending into hell?" she asks.

"I always think with Christie, what she's interested in is less really about the murder and the solving of the murder, but really about watching people lie. How people lie, the lies they tell themselves and the lies they tell everyone else to keep safe," she adds. "That's never going to not be relevant."

"Christie is quite warped in her own way, that's why we love it," Sewell muses.

"It's like reading something that's a cross between An Education, The Wicker Man and Jacob's Ladder," he compares. "There's an element to this story that is really quite surprising. It reminded me of a phrase Hitchcock once made about one of his film scripts: 'It's a nice, nasty little piece'."

WHAT'S NEXT?

While he's not ruling out diving into this world once more - I would love to do a cosy one sometime too!" - Sewell's next release comes in the form of drama film, The Father.

"[I'm starring opposite] Anthony Hopkins and Olivia Colman," he notes, the picture having premiered at the Sundance Film Festival this January.

"It's written by Florian Zeller, the playwright [it's a play but he's directed the film co-written by Christopher Hampton] and it's a wonderful script about an old man who is kind of losing it, and who is living with his daughter and his daughter's husband [who I'm playing]."

And Phelps - is she likely to pursue another Christie novel or is this her lot?

"I always thought I'd like to write a quintet and I've done it, but I'd never say never!" she fesses. "Maybe there would be something else, another way of framing these stories to give them a reason to be?

"Because being able to say this was a quintet about the 20th century gave it a shape and a focus," she rationales. "And finding another shape and a focus, that's never hard. I just make things up!

"I do still fancy a bit of Endless Night, though, because it's so mad..."

The Pale Horse, BBC1, tomorrow, 9pm.