[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/the_bletchley_circle_4.jpg]]
[[caption-width-right:350:L to R: Alice, Lucy, Susan, Millie, Jean]]

''The Bletchley Circle'' is a 2012 miniseries about a quartet of women who solve crimes in 1952. The four worked as codebreakers during World War II, though they're not allowed to say anything about it anymore, of course. Their new careers as criminal investigators begin when Susan, one of the four, takes advantage of her free time as a middle-class housewife to investigate a pattern in a series of murders, using the information available from Creator/TheBBC.

A second miniseries of two two-episode stories aired early in 2014. While the show was not renewed, a spinoff series known as ''Series/TheBletchleyCircleSanFrancisco'' was launched in 2018.

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!! This miniseries provides examples of:

* AbandonedHospital: [[spoiler:The killer's base of operations]] in the first series.
* BadGuysPlayPool: In the second half of the second series, Jane and Lucy are trying to track down whoever [[spoiler:took Millie]], and end up in a pool hall.
-->'''Jane:''' Did you see him with any bad types?
-->'''Bookie:''' It's all bad types in here, love.
* BadassLongcoat: The four ladies all frequently wear long coats, and they all look sexy and badass in them. Justified because it was the fashion at the time.
* TheBaroness: Somewhere between the two types. She's not unattractive, but not a sexpot. A "woman of a certain age", but willing to engage in cold-blooded torture. In the second series.
* BlackMarket: [[spoiler:What Millie and Jasper are involved in]] during the second half of series 2.
* BookEnds: The series starts with Susan noticing a spiral pattern in the four murders. It ends when she notices a spiral pattern in all 12.
* BreakTheCutie: Everyone but especially Lucy. Heck, she gets slapped about by two different men twice in one day.
* CliffHanger: At the end of the second episode, Susan goes into an abandoned hospital with a strange man...
* ClassyCane: Jean gains one thanks to the events at the end of the first story of the second series. They dress her up to the nines for an undercover operation in the second.
* CouldntFindAPen: While marking out the train routes in the first series, the girls use Millie's lipstick to trace the lines.
* DadTheVeteran: Timothy. But he does not seem to be much of a hardass.
* DarkerAndEdgier: The second story of the second series. It very thoroughly shakes Millie up.
* DeadManSwitch [=/=] MexicanStandoff: At the end, Susan has a gun, the killer has a grenade.
* DomesticAbuse: Lucy's husband, Harry, is controlling and physically abusive.
* EurekaMoment: Several, including:
** When Susan realizes the killer finds his victims on trains.
** When Susan realizes the first victim ... isn't. [[spoiler: She's the eighth, at least.]]
---> '''Susan''': The first time you baked a cake, what happened?
:::: Unfortunately for the ladies' credibility with the police, sometimes the killer is further ahead than they had realized.
* FallGuy: [[spoiler: Gerald Wiggins]] The killer chooses a patsy first, ''then'' goes hunting for victims, and finally plants incriminating evidence.
* FourGirlEnsemble:
** TheLeader: Susan. She does love her husband and children, it's just that they're not enough for her, so she decides to hunt a serial killer. She sees the patterns and provides the group with its drive to succeed.
** TheLancer: Millie. Whereas Susan settled down, Millie took her own advice to "Never be ordinary" and traveled the world. Only now she's working as a waitress for a pervert. Until she tells him where to shove it. Where Susan sees patterns, Millie tries to think outside the box.
** TheBigGuy: Jean. She's the TeamMom, who keeps everyone on point. She also pulls out the stops and threatens someone with blackmail in order to get her information.
** TheSmartGuy: Lucy. She's the small, naive one, but she can also memorize entire novels of data in a single sitting.
* FreudianExcuse: The killer was trapped under rubble with a dead woman for three days during the war, after which he was ''different''. However, the team's investigation showed that all that did was exacerbate his already existing tendencies (the woman he was obsessed with, whose death he's repeatedly recreating, filed a complaint against him three months before the bombing that killed her and trapped him with her body).
* GloryDays: It's Susan's longing to recapture the sense of excitement and importance that she felt during the war years that galvanises her to go [[PuttingTheBandBackTogether get the team back together]] and go in search of a serial killer.
* HiddenInPlainSight: The killer. They realize in the first episode that he's a ticket taker or something like that. [[spoiler: Subverted: It turns out that the killer killed ''seven'' other girls before the series started and framed others for the crimes. This time he's framing a railway guard who's rather simple thanks to a head wound.]]
* {{Housewife}}: What Susan and Lucy became after the war. Millie does her best to avoid this trope.
* ILoveTheDead: The killer in the first episode. The first shot after the codebreaking intro is of the killer fondling a corpse. It's understatedly graphic.
* TheIngenue: Lucy is a little younger and a ''lot'' more innocent than the three others.
* LighterAndSofter: The first story of the second series. It deals with some nasty stuff, but it's not a psychopathic serial murderer/necrophiliac.
* MamaBear: Played straight and inverted in the second series. Lizzie is very defensive of her biological mother. Although said biological mother had to give her up at birth, said mother was ''also'' willing to take the rap for a murder she thought she'd committed.
* {{Masquerade}}: The four ladies aren't allowed to talk about their work as codebreakers thanks to the Official Secrets Act. Susan brings them back together to start a "book club". She also doesn't want to tell her husband that she's tracking down a serial killer.
* NearRapeExperience:
** Lucy is used as bait to try and draw the killer out. Unfortunately, they snag a common date-rapist instead of the intended serial-killer/necrophiliac.
** In the second series, Millie has a very unpleasant encounter with her black-market-partner's Maltese suppliers. She manages to talk her way out of it, bargaining her services as the front man for their black market goods. But, on getting out, she pushes her luck with the guy who drove the windowless van...
* NotTheFirstVictim: In Series 1, Susan and the other women figure out early that, although they are currently investigating a single murder, there's no way that the killer got as far as he did without messing up, which means he has other "messier" victims. It turns out that [[spoiler:he's done this seven times and has a FallGuy picked out every time, often first.]]
* PhotographicMemory: Lucy has a perfect memory, and is also a page-at-a-glance reader. PlayedForDrama later on.
* PluckyGirl: Susan, the bored mother of two, talks her way into a meeting with a police.
* PutOnABus: Susan's husband is posted to India midway through Series 2, so she is absent from the latter two-part story of that season. The show's cancellation meant the bus never had a chance to come back.
* RapeIsASpecialKindOfEvil: Referring to the Maltese and their trafficking in girls. Neither the police nor the Circle really care about scents and nylons, but as soon as it comes out that girls are being sold out of a hotel lobby...
* ReasonableAuthorityFigure: The general Susan talks to in the second episode of the second series. It turns out he's ''not'' behind the events, and as soon as she gives him all her information, he immediately works out what has happened and absolutely forgives Susan. He even provides her a car so she can go see her friends, one of whom has been hurt.
* SexSlave: Millie's partner's suppliers don't just smuggle goods. They traffic girls out of the USSR and other Warsaw Pact countries and into their hotel. The girls' parents ''think'' they're getting them jobs as chambermaids...
* ShellShockedVeteran: Susan in the second series. She's having a lot of trouble dealing with the fact that she was stalked and almost killed by a twisted psychopath.
* SurprisinglyRealisticOutcome: The entire series is an effective deconstruction of tropes associated with AmateurSleuth stories....
** The police distrust Susan's hunches not because she is a woman (or at least, not ''only'' because she's a woman), but because her first hunch leads to nothing, damaging her credibility.
** After the end of the first series, Susan [[ShellShockedVeteran suffers from Post-Traumatic Stress Disorder]] and has to be cajoled back into sleuthing by her friends. Halfway through the second series, [[ScrewThisImOuttaHere Susan has had enough,]] [[PutOnABus and she is happy to accompany her husband when he is promoted to a new position in India.]]
** While the women are very good at skills associated with code-breaking (mathematics, memory, logic, etc.), they clearly have trouble with other aspects of detective work.
** When Jean is shot in the second series, it is stated to be OnlyAFleshWound ... but she has permanent damage to her leg, having an ugly scar and needing a cane in the second half of the season.
** The women get together to solve a mystery all of three times, each of them several months (or years) apart (though they would have had more if the show had not been cancelled). The first time is partly out of moral outrage at the killer and partly out of yearning for their GloryDays as code-breakers. The second and third times, one of their own is in danger, and ItsPersonal.
** Susan's constant going out to her "book club" causes considerable strain on her marriage.
** While Alice's name is cleared in season 2, the stigma of a murder accusation follows her, making it impossible for her to find work. Eventually she takes on an assumed name.
* StepfordSmiler: Susan's life as a housewife is a light Type A.
* TeamMom: Jean is older than the other three and was their supervisor in the war.
* TechnologyPorn: The opening credit sequence is chock full of WWII-era code equipment in use.
* TrappedByGamblingDebts: Millie's partner. He stole from his suppliers to bet on the dogs. [[spoiler:They slit his throat.]]
* VomitDiscretionShot: In the second series, after Millie discovers that the Maltese smugglers killed her partner.
* WickedCultured: The killer can quote Latin poetry.
* WorthyOpponent: The killer, by the end, comes to see Susan this way. He's enthralled and delighted that she is the only person ever to figure him out and see past the false trails he was laying.
* WrenchWench: Alice repairs an old, out of order Enigma machine in the last episode of the second series.
-->'''Millie:''' You're talking to the machine again.
-->'''Alice:''' They like to be talked to.
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