Christmas TV: Scarborough-born Penelope Wilton on BBC's latest Agatha Christie adaptation Murder Is Easy

It’s a strange conversation starter, but things get stranger when Fitzwilliam steps off the train to the sound of screams.

Then his mind is preoccupied with the murders Miss Pinkerton told him about, so he decides to check out the village – “a place where murder is easy”, he says, for himself.

Across two episodes, Rye Lane and Industry star David Jonsson plays Fitzwilliam as he delves into the mystery in a BBC adaptation of Agatha Christie’s 1939 crime novel Murder Is Easy.

He’s joined by a talented cast including The Rings Of Power’s Morfydd Clark as Bridget, Tom Riley as Lord Whitfield, Douglas Henshall as Major Horton, Tamzin Outhwaite as Mrs Pierce, and Mathew Baynton as Dr Thomas.

Miss Pinkerton is played by Yorkshire’s own Penelope Wilton, whose home town is Scarborough.

Her character, says Wilton, “lays out the entire plot of the story and from then on it's for Fitzwilliam to unravel”.

She says: “I thought it was a very good script. They brought it up to date, not in period, but in attitude. And it's got all the things that Agatha Christie is well known for. It happens in a small place outside London, a small sleepy village, where enormous emotions are going on. And they really are enormous – of love, of envy, of all sorts of things. And she taps into that world of people in a very English way, keeping all these emotions to themselves, until it sort of bursts forth in this rather, I'm afraid to say, rather aggressive way.

"I think audiences will find it engaging. Agatha Christie has a very good record because she tells a very good story. It's a page-turner. Her great thing was plot and character. Her characters were often similar, but the plots were always very different. And I think this is an extremely well-told story and extremely well-told in this series.”

Wilton is no stranger to period dramas, however, having starred in the likes of Downton Abbey and the 2005 film of Pride & Prejudice, although viewers might just as easily recognise her from television show Ever Decreasing Circles or alongside Ricky Gervais in After Life.

She says: “I haven't actually inhabited the world of the 1950s before. I've inhabited much earlier: the 16th, 17th, 18th century, but very little of the 19th or 20th century. So it's been fun because when I was a child, which was in the late 50s, I remember quite a lot of the fashions. Older people, people that are my age now, used to wear the sort of clothes that I’m wearing as Miss Pinkerton in the series.

"The costumes are wonderful and also the thing about the costumes is that a lot of these dresses, in fact, the dress you can see me wearing on the train as Miss Pinkerton was an original dress from that period. And they're beautifully made so they stood the test of time.”

Jonsson’s character, Luke Fitzwilliam, is from Nigeria, where he is in a senior ranking military position.

The actor says: "He’s an attache to the British Colony, essentially. And he is doing quite well there but, of course, he’s coming to London to kind of ‘better’ himself. He’s got a job at Whitehall waiting for him. So that’s why he finds himself in England. He’s got his life mapped out ahead of him, which quite swiftly gets derailed by an encounter with a stranger.”

Wilton’s character “quite quickly charms him,” he says.

"I think just by her natural energy, which is quite infectious, but she’s also got information about a number of horrible deaths – which she thinks were murders but have been brushed off as accidents – in her tiny English village.

“I think out of a certain moral compass Luke is naturally taken to it and then, without giving too much away, something quickly happens which forces him into action, following her trail to catch a murderer.”

Why did he want to be involved in the series?

Jonsson says: “First of all, this has got to be the most excited my mum’s been about me doing a job, ever!

“Agatha Christies mean more than just a regular murder mystery. They’re a British institution – they bring people together and encompass a lot of what it means to be British. So it was great to read a script that felt not only new and fresh with an interesting mercurial character, but also brings in a whole new culture that we’ve never seen in an Agatha Christie before.

“Having a Black hero felt incredibly fresh and exciting to me. I feel very privileged that I’m able to do that.”

What does he think people are going to love most about it?

“I think people are going struggle to guess the killer – or killers – with this one.

“I think you are in for a rollercoaster ride – looking at one thing that actually means something else.”

Murder Is Easy is on BBC One on Wednesday, December 27 at 9pm, and BBC iPlayer.