ABC Murders writer Sarah Phelps to adapt another Agatha Christie novel

"When I was working on And Then There Were None [in 2015], there was a little voice in my head saying that I could write a quintet and cover 50 years of the tumultuous blood-soaked 20th century within the genre of the murder mystery. Having now done the 1920s, the beginning and end of the '30s, as well as the 1950s, the next one is going to be set in the 1960s."

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After And Then There Were None, BBC1 went on to screen Phelps' dramatisations of The Witness for the Prosecution, Ordeal by Innocence and The ABC Murders for BBC1. Now, RadioTimes.com understands that The Pale Horse – written by Christie in 1961 – will be the next whodunnit to be tackled by the screenwriter, with a transmission date yet to be confirmed.

The Pale Horse is a standalone novel that centres around the character of Mark Easterbrook, who probes the murder of a Catholic priest struck dead in the fog after hearing the confession of a dying woman. Phelps's version of the story will follow Death Comes as the End, a Christie tale set in ancient Egypt that is to be adapted by Vanity Fair writer Gwyneth Hughes.

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Previous Christie TV dramas penned by Phelps have attracted some criticism thanks to the change of killer in Ordeal by Innocence and an added backstory for John Malkovich's Hercule Poirot in The ABC Murders. Phelps said she recognised that feedback could be "brutal" but that she'd deliberately made it her mission to subvert viewers' expectations:

"Agatha Christie plants these little clues in her books and I pick them up and run with them. I'm honouring the secret, subversive Agatha. There's something dangerous about her – and there's a lot of academic work to be done on the tension in the novels between the book she knew the public wanted to read and the one she wanted to write. I always think I'm doing the version of the book she wanted to write."

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Asked how she felt about her take on Poirot being discussed on social media over the festive season, Phelps said: "Well, who would have thought that a Belgian detective who came into creation in 1920 and who Agatha Christie came to loathe would become a talking point? Funnily enough, the one question I kept asking while writing it was, 'why did Agatha hate him?' And I believe it's because she made him fussy and didn't let him have a heart.

"I had to really love my Hercule, which is partly why I gave him this past. I wanted to believe in him, so that when he gave his word to the dead, he meant it. It gave him drive."