Wicked Little Letters: The true story the Jessie Buckley film is based on - and what's been changed

It's set to be released in British cinemas on Friday, February 23, and it is already looking like being a hit with audiences and critics alike.

The film is the feature debut from director Jonny Sweet, who in his standup career won the 2009 Edinburgh Comedy Award for best newcomer.

And he's brought a few of his friends along for the ride, with Edinburgh favourite like Tim Key and Lolly Adefope featuring in supporting roles.

Here's what you need to know about the film - and the true story it's based on.

What is Wicked Little Letters about?

Olvia Coleman plays Edith Swan, a devout and upstanding Christian woman who lives with her parents in the English seaside town of Littlehampton. When a loud, sweary, yet charming Irish immigrant Rose Gooding (played by Jessie Buckley) moves in next door with her daughter and boyfriend the pair at first become friends, before a series of misunderstandings (and Edith's domineering father) see them fall out. When Edith starts to receive a series of obscene (and hilarious) poison pen letters, Rose becomes the prime suspect. As the letters start to appear on the doorsteps of more of the town's residents a female police officer teams up with a group of women to prove Rose is innocent - battling sexism and snobbery along the way.

Is Wicked Little Letters based on a true story?

Many of the events portrayed in the film did actually happen in the the town of Littlehampton and the so-called 'Littlehampton Letters' were a media sensation in the 1920s - with the Daily Mail labelling it 'the Seaside Mystery’. The book 'The Littlehampton Libels: A Miscarriage of Justice and a Mystery about Words in 1920s England' by Christopher Hilliard tells the true story.

Was Rose Gooding a real person?

Rose Gooding was a real person who was wrongly sent to jail twice in the case of the poison pen letters. She was English rather than being Irish as portrayed in the film though, and lived in Littlehampton with her ship's cook husband Bill, her unmarried younger sister Ruth Russell and five children (four illegitimate and one son she had with Bill). She was a huge local character and known for having blazing rows with her family and being unafraid to use salty language.

Was Edith Swan a real person?

Again, Edith Swan was a real person who was accused of sending obscene letters in 1921, but in the true story they were largely sent to her neighbours Violet and George May. She did, however, also send herself letters in order to demonstrate her innocence. She was a 30-year-old laundress who lived with her parents and several siblings and nearly got away with the crime as, despite a wealth of evidence, the judge at the trial declared her "the kind of Englishwoman who was incapable of swearing".

How was Edith Swan caught?

The truth of Edith Swan's arrest is even stranger than the events portayed in the film. Suspicion already hung over her after police searched her home and found a piece of paper which had traces of a letter on it (she claimed her father had found it outside). The key piece of evidence was found when police installed a periscope in the post office's mailbox to see who was posting letters. Two letters posted by Swan were retrieved by a post office clerk and it was shown beyond doubt that she was the author as the stamps (as shown in the film) had been marked with invisible ink before being sold to the suspect.

Was Gladys Moss a real person?

The police officer portrayed in the film was a real person - Gladys Moss became Sussex' first female police officer on her appointment in 1919 and was one of 30 women who applied for the role. She lived in Worthing but learned to ride a motorbike and covered cases across the county for 20 years. A blue plaque at Worthing Assembly Hall marks her achievements.

It's also true that she was instrumental in catching Edith Swan. While monitoring Swan from a neighbours' graden shed she saw Swan throw a letter into a garden belonging to her victims.

What happened to Edith Swan?

Edith was belatedly found guilty of writing the letters in 1923 and was sentences to 12 months in jail "with hard labour".