The sweary true story behind Olivia Colman comedy Wicked Little Letters

The sound of extravagant, English-accented swearing is emanating from living rooms across the UK right now. At least, that must be true if the Netflix Top 10 is to be believed given the film currently hovering around the top spot is Wicked Little Letters — the foul-mouthed comedy starring Olivia Colman and Jessie Buckley.

Released in cinemas earlier this year, Thea Sharrock's film follows the travails of 1920s spinster Edith Swan (Colman), who is troubled by the arrival of insulting, uncouth letters aimed at her. She immediately suspects her neighbour — the considerably less prim and proper Rose (Jessie Buckley). But we quickly realise there's more to the mystery than first appears.

Note: There are spoilers for Wicked Little Letters ahead.

Fascinatingly, the ludicrous events of Wicked Little Letters are grounded in a very real controversy, which took place in the West Sussex seaside town of Littlehampton. It was a sensation in the national press at the time and even formed part of a debate in Parliament. Prepare your most creative epithets because we're diving right in.

The real Edith and Rose became fast friends when the latter moved into the house next door to Edith with her three-year-old daughter, who was scandalously born out of wedlock. They shared knitting patterns and recipes, which was all very wholesome.

Things changed, though, around the spring of 1920. The duo fell out over a shared bit of garden and Edith reported Rose to the NSPCC over treatment of her daughter. So when Edith started receiving very offensive, abusive letters soon afterwards — most of the letters in the movie are taken directly from the real-life case — the suspicion naturally fell on Rose.

Read more: Wicked Little Letters director struggled to contain laughter during filming (Cover Media)

Edith launched a private prosecution and Rose was ultimately convicted, serving several months in prison. When Rose was back on the streets, the letters resumed and she was convicted again — this time landing a 12-month prison term with hard labour. But with Rose locked up, letters still circulated.

At this time, the authorities began to suspect Edith herself, with handwriting from Edith's home appearing similar to the letters. This was compounded when Edith sent a notebook full of insults to the police, claiming she found it by Rose's house. Edith simply pushed her luck too far.

Rose's conviction was overturned by an appeal court and she received a hefty compensation payout. The film then brilliantly shows what happened next through the eyes of PC Gladys Moss (Anjana Vasan), who spearheads the investigation into Edith. In 1921, Edith was arrested for writing an abusive, libellous letter to a different neighbour, but she was cleared of wrongdoing by a jury.

Read more: Olivia Colman had 'no idea' Wicked Little Letters was based on a true story (BANG Showbiz)

It took until 1923 for things to actually come to a head — the movie crunches this timeline down for obvious reasons — and for justice to be served. The police and the post office carried out a sting operation, duping Edith into purchasing postage stamps marked with invisible ink. When one of these stamps turned up on an abusive letter to a sanitary inspector, Edith had nowhere to hide.

Despite this evidence, the judge at Edith's trial couldn't believe that she could be responsible, saying that "her demeanour in the witness box was that of a respectable, clean-mouthed woman", according to the Brighton Argus newspaper. The jury duly convicted her, though, and she received the same prison sentence previously handed down to Rose.

Watch: Explaining the Wicked Little Letters true story

In the film version, Edith ultimately admits her guilt when cornered by the sting operation. However, in real life, she continued to maintain her innocence. Nonetheless, Rose was fully exonerated and was able to move on with her life, free of the stain of the allegations.

Read more: Wicked Little Letters: this hilarious detective story is a meditation on the art of swearing (The Conversation)

The true story is perfect for a movie like this, in that it's serious enough to bring about real emotions while also being incredibly silly. On the big screen, it gives Jessie Buckley and Olivia Colman plenty of opportunities to wrap their tongues around some incredibly elaborate swearing — and ultimately, do we want more from a movie than that?

Wicked Little Letters is streaming in the UK now on Netflix.