Wicked Little Letters: We meet the cast of the poison-pen mystery drama

In the quaint town of Littlehampton lives the deeply conservative, pious Edith Swan, played by Olivia Colman.

She shares a bedroom with her elderly parents – her overbearing father Edward played by Timothy Spall, and kindly mother played by Gemma Jones – leading a quiet life in a terraced house next door to the rowdy Irish migrant Rose Gooding and her young daughter Nancy.

Rose, played by Jessie Buckley, lights up sleepy Littlehampton like a stick of dynamite. She’s an electric presence, often up to boisterous activities like drinking and telling filthy stories, and she and Edith strike up an unlikely friendship.

However, when Rose stands up against Edith’s strict and disapproving father at his birthday party, her bond with Edith sours.

Soon after the face-off, Edith and her fellow residents begin to receive shocking letters filled with imaginative insults and profanities, and all fingers point towards the indelicate newcomer Rose.

As Rose faces imprisonment and losing her beloved Nancy, Woman Police Officer Gladys Moss, played by Anjana Vasan, senses something amiss.

Despite being constantly undermined by her male colleagues, she begins a sleuthing operation to clear Rose’s name and find the true hand behind the vulgar letters.

The bizarre true story makes perfect fodder for a big screen romp, made all the more thrilling by its brilliant cast.

“It was just silly,” grins The Crown and Peep Show star Olivia Colman, 50.

“Jessie is one of my favourite human beings in the world – we got paid to go to work together holding hands, skipping in every day, and finding these hilarious ways of insulting each other very funny.”

Come on Colman, give us a taste?

“Like, Rotten old onion, stinky old bitch,” she smiles.

“You can do better than that, give it to me,” laughs The Lost Daughter and Women Talking’s Buckley, 34.

As Buckley suggests, Colman’s onion-scented insult only scratches the surface of the inventive vulgarity on display in Wicked Little Letters. As the letters get more scathing, their content gets more hysterical, pushing even the sanctimonious Edith to breaking point.

“I loved the complete flip of her, of doing the ‘butter wouldn’t melt’, and then when she gets to have a good old rant – just joyful to play,” says Colman.

“I do think I over-egged slightly, I was enjoying it so much, doing the comedy eye batting. I knew I’d enjoy playing her.”

Buckley adds that she loved Rose’s “wild, tenacious lifeforce and that she was uncompromising about that and just really wanted a good time, even though the whole world was chastising her, judging her because she was a single mother”.

“But she had so much strength and fun and joy about her, and I just loved playing her,” she says.

“She’s great fun.”

Playing Edith’s father Edward, describing him as, “for want of a better word, a typical old Edwardian bastard”, is Mr Turner and Harry Potter star Timothy Spall, 66.

“He is controlling, he is aggressive, he is vile at times, but also is riddled with all sorts of terrible vulnerabilities that he’s not come to terms with. So it’s great,” he says of his character.

“Olivia is undoubtedly two very remarkable things. She’s a very, very brilliant actress, and a very, very lovely person. That is a truth universally acknowledged,” he adds of his co-star.

“That is very, very helpful. As is Jessie and Anjana, it was a great cast, a very, very good bunch of fellow funsters.”

Anjana Vasan, whose previous roles include parts in Sex Education, We Are Lady Parts and Killing Eve, says that she enjoyed getting “to be Agatha Christie for a bit” as WPC Gladys Moss.

“It was fun playing someone who is in a uniform and a hat that’s, like, one size too big, and trying to figure everything out for the first time,” she says.

“But also, I think the movie has one foot in the 1920s and one foot now. So I feel like even though I was playing a historical character, I didn’t feel like I had to tap into something that was unusual for someone like me to understand what it might feel like to have someone show microaggressions towards you, or underestimate you. I think any woman can relate to that feeling.”

It is this blend of the comedy and drama in the mystery film that gives it an edge, one that grounds it in reality and really endears you to its characters, despite the absurdity of their lines and the extraordinary plot.

“I’d done quite a few heavy, dark, drama things before this, and I so wanted to do something that was light and fun, and be able to be really silly and naughty on set,” says Buckley.

“There’s scope for all kinds of films in the world, and I love going to watch all of them, but I think a good comedy – you can’t beat it.

“To really go and have a belly-laughing giggle, and get a huge box of popcorn, a glass of wine, and then come out and just feel like you just want to be so naughty.”

“I suppose that’s kind of the dream, isn’t it, to be able to do both of your big loves in one thing,” says Colman, who has won a slew of prestigious awards in both comedy and drama.

“I think the best comedy has some darkness, that appeals to me. And this just naturally had both things.

“It’s true, it was debated in Parliament, and two women went to prison, but the whole nation was gripped by this. It was like the Wagatha Christie of its time. And the swearing is funny. So it’s all of those things.”

“It’s got it all,” she summarises. “Go watch it.”

Wicked Little Letters is in UK cinemas now.