Wicked Little Letters is a British comedy not to be confused with Pretty Little Liars, Big Little Lies or Wicked Little Lettuce, hopefully the next Liz Truss book.

Based on a real case from the 1920s, Wicked Little Letters is set in the seaside town of Littlehampton, where a supercilious Christian (Olivia Colman, brilliant as ever) starts receiving profane letters through her door. Her sweary neighbour (Jessie Buckley) becomes the prime suspect in the police investigation and subsequent court case, owing to her social status as an unwed mother and Irish immigrant. They should have called it Anatomy of a Scrawl.

Though it raises some interesting discussion of sexism and parallels with modern-day trolling, the picture completely fails to balance its twee Comedy with darker themes of domestic abuse. The talented cast relishes the script’s obscenities, but the swearing is not really inventive enough to be funny, and there a few other jokes of note in Jonny Sweet’s screenplay (except for one stolen from The Simpsons). Thea Sharrock’s direction also brings a slowness to the dialogue that impedes the cast’s comic timing, as though they’re communicating on a satellite delay.

There is always joy in seeing Tim Key, Lolly Adefope and Joanna Scanlan, but they are given scant opportunity to put their stamp on a movie whose mystery is mispaced and colourblind casting misplaced. The film explores how classism and xenophobia intersect with sexism, yet makes the conscious choice to ignore racism, in a way that unfortunately draws attention to that decision.

The feature deserves its dues for depicting the dangers of repression and suppression, although compared to recent comedy/mystery flicks like Knives Out and See How They Run, Pretty Big Lettuce ends up feeling limp.