History Series / SlowHorses

* PoorCommunicationKills: If Cartwright had just realized his contact was identifying a suspected terrorist by "white shirt, blue tee" and not the other way around, the entire opening scene mess at the airport (not to mention scores of events that followed) could have been avoided.

* PrivateIntelligenceAgency: River was scouted for consideration to join a [=PIA=] in Season 2 called Elessar. However, he said that he wasn't given an offer due to the mess that happened [[spoiler:when River made a mess on the MI5 training op.]]

** Taverner deconstructs WellIntentionedExtremist by showing how much damage an ''incompetent'' one can cause. [[spoiler: Her FalseFlagOperation allegedly had good intentions, but when multiple blunders on her part cause it to go OffTheRails, she keeps digging herself deeper in a desperate attempt to throw anyone but her under the bus for her own failures. As a result, she's part of Season 1's BigBadDuumvirate alongside the Sons of Albion, and eventually, the primary villain of the third season]].

** Taverner deconstructs WellIntentionedExtremist by showing how much damage an ''incompetent'' one can cause. [[spoiler: Her FalseFlagOperation allegedly had good intentions, but when multiple blunders on her part cause it to go OffTheRails, she keeps digging herself deeper in a desperate attempt to throw anyone but her under the bus for her own failures. As a result, she's part of Season 1's BigBadDuumvirate alongside the Sons of Albion]].

* InstaDeathBullet: [[spoiler:In the final episode of season 2, it takes exactly one bullet to the back for Pashkin to drop stone dead.]]

'''Lamb:''' Gor, actually...maybe not.

[[quoteright:350:https://static.tvtropes.org/pmwiki/pub/images/60c389ac_94de_4e50_bc90_0cb782ec2668.jpeg]]

* SparedByTheAdaptation: In season two, [[spoiler:Spider is shot by Pashkin, but he's up and about again for season three. In the original novel, ''Literature/DeadLions'', he's left on life support, and it's implied that he's died by the end of sequel ''Literature/RealTigers'' that he's died, as River finds his hospital room empty]].

** In the novel ''Literature/DeadLions'', [[spoiler:Andrei Chernitsky genuinely leaves the country after he kills Dickie Bow, playing no further part in the plot. In the series he remains in the UK, and is eventually shot dead while trying to kill David Cartwright]].

* DiesDifferentlyInAdaptation: A minor one. [[spoiler:The book doesn't feature Taverner and Judd's conversation about Hobden, and it's implied that Judd arranges his death in a hit-and-run. In the series he's clearly killed by [=MI5=] and Duffy pushes him under a truck]].

* DeathByAdaptation: [[spoiler: In the book, the only one of the three kidnappers who's definitely killed is TheMole, Alan Black. In the series, which has four, one's shot after a quarrel about Hassan's execution and another's shot by the security forces at the docks]].

* SmugSnake: Spider Webb is on track to climb the ladder at Regent's Park and loves to lord his superior political position over others, especially River.

* TerminallyIllCriminal: Nikolai Katinsky was one of the greatest [[TheSpyMaster Soviet Spymasters]] during the Cold War, setting up numerous sleeper agents and moles in the highest ranks of British Intelligence. Following escaping to America and living for years as a seemingly unassuming bureaucrat, upon being diagnosed with terminal cancer and given six months left to live, he decides to embark on a final quest for revenge against Jackson Lamb, by robbing the Glasshouse, as Lamb was responsible for killing his operative all those years ago.