While we know and love Anna Maxwell-Martin for her roles in Motherland and Line of Duty, she's also got a brilliant back catalogue of content for digging into. If you haven't watched The Bletchley Circle, it's essential viewing for fans of murder mysteries.

Here's everything you need to know about the three part mini-series, from what it's about, who else makes up the cast and where you can watch it now.

What is The Bletchley Circle about?

The Bletchley Circle is a mystery drama set after World War II, in 1952. It follows four British women called Millie, Susan, Jean and Lucy, who worked as codebreakers in Bletchley Park - a top secret wartime intelligence centre where codes from the German military were hacked.

The mini-series follow Anna Maxwell Martin's character, now a housewife, who notices a pattern unfolding in murders across London. When police dismiss her theories, she begins a covert investigation into what's going on, alongside her former colleagues at Bletchley Park.

According to the Channel 4 description, "Drama about four fictional ex-Bletchley Park operatives who team up to solve murders. With Anna Maxwell Martin, Rachael Stirling, Julie Graham and Sophie Rundle."

"anna maxwell martin is stellar": the forgotten murder mystery drama now streaming on channel 4pinterest
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Who's in the cast of The Bletchley Circle?

As well as a stellar performance from Anna Maxwell-Martin, who you'll know from Until I Kill You and Code 404, as Susan Gray, the housewife who reunited her ex-colleagues to investigate the murders, the cast includes:

  • Rachael Stirling from The Serpent Queen as Millie Harcourt, a former codebreaker who now works at the British Library
  • Sophie Rundle from Bodyguard and Peaky Blinders as the youngest member of the group Lucy, who has a photographic memory
  • Ridley's Julie Graham as Jean McBrian, their former supervisor at Bletchley Park who now works as librarian
  • Doctor Who's Mark Dexter as Susan's husband Timothy Gray
  • Steven Robertson from Shetland as Malcolm Crowley, a war veteran who becomes essential to their investigation
"anna maxwell martin is stellar": the forgotten murder mystery drama now streaming on channel 4pinterest
Courtesy ITV

Where can you watch The Bletchley Circle?

WATCH NOW There are three 45-minute episodes in season one, which were originally released in 2012, and you can watch them for free on Channel 4. There was also a season 2 of The Bletchley Circle, which contains four episodes and was released in 2014, which you can also watch on the streaming platform. You're welcome!