Slow Horses is a British spy thriller television series based on the Slough House series of novels by Mick Herron. The series premiered on Apple TV+ on 1 April 2022.[1] The second series, Dead Lions, premiered on 2 December 2022.[2] In June 2022, the series was renewed for a third and fourth series.[3] The third series premiered on 29 November 2023.[4] Showrunner Will Smith has stated that the fourth season should be released by the end of December 2024.[5] In January 2024, it was renewed for a fifth series, which will be based on the fifth book in the series, London Rules.[6]
Premise
Slough House is an administrative purgatory for MI5 service rejects who have bungled their job but have not been sacked. Those consigned there are known as "slow horses". They are expected to endure dull, paper-pushing tasks, along with occasional mental abuse from their miserable boss, Jackson Lamb, who expects them to quit out of boredom or frustration. Life in Slough House is defined by drudgery. Yet the Slow Horses somehow get involved investigating schemes endangering Britain.
Cast and characters
Main
Gary Oldman as Jackson Lamb, the head of Slough House who is slovenly and rude, but has a sharp and devious mind, and retains his abilities as an experienced intelligence officer.
Jack Lowden as River Cartwright, an up-and-coming MI5 agent shunted aside to Slough House after a very public training-exercise mistake.
Kristin Scott Thomas as Diana Taverner, the Deputy Director General of MI5 and head of operations and designated "Second Desk".
Slough House
Saskia Reeves as Catherine Standish, the office administrator and a recovering alcoholic.
Olivia Cooke as Sidonie "Sid" Baker (season 1), a competent MI5 agent inexplicably assigned to Slough House.
Rosalind Eleazar as Louisa Guy, assigned after a tail operation went badly.
David Walmsley as Larry, a member of the Sons of Albion.
James Faulkner as Charles Partner (in flashbacks), a former Director General of MI5 during the Cold War, whom Standish worked for as his personal assistant.
Notable other characters appearing in Series 2 (Dead Lions) include:
Rade Šerbedžija as Nikolai Katinsky, a former KGB agent living in exile in London after defecting at the end of the Cold War.
Marek Vašut as Andre Chernitsky, a former KGB operative and assassin who operated during the Cold War.
Slow Horses is based on the novel of the same name by Mick Herron, which is part of the author's Slough House series. It tells the story of a team of British intelligence agents who have all committed career-ending mistakes, and subsequently work in a dumping ground department of MI5 called Slough House.
After a serious mistake, caused by a colleague but blamed on him, during a live training exercise at Stansted Airport, MI5 agent River Cartwright is demoted to dead-end work at Slough House in lieu of being fired. He is assigned by his superior Jackson Lamb to carry out surveillance on Robert Hobden, a journalist associated with far-right politicians Peter Judd and Roger Simmonds. His colleague Sidonie "Sid" Baker has also been assigned to Hobden, discreetly copying the contents of his USB flash drive in a café. River is then instructed to deliver the drive to the service's headquarters at Regent's Park, much to his surprise.
Hobden makes a series of calls to journalist colleagues alleging he has information that an "attack is imminent". River visits his grandfather, who reveals Hobden was blacklisted when his name appeared on a leaked donor list of the British Patriotic Party, and blamed MI5 for his troubles. He warns River that if MI5 are using Slough House to look into Hobden, it is because there is risk and they want plausible deniability. Standish attends an Alcoholics Anonymous meeting. British-Pakistani student Hassan Ahmed is kidnapped by the far-right group Sons of Albion, who announce they will behead him on livestream at sunrise the following day. River breaks rank and leaves Slough House to further investigate.
2
2
"Work Drinks"
James Hawes
Will Smith
1 April 2022 (2022-04-01)
Hassan's kidnappers – Moe, Larry, Curly and Zeppo – hold him hostage in a London terrace basement, with it transpiring that Simmonds is behind the kidnapping. River, having copied the contents of Hobden's USB drive before delivering it to Regent's Park, realises it contains no information and manipulates a rival, James "Spider" Webb, into confirming the same. Standish begins having flashbacks to the death of a former colleague of hers and Lamb's, Charles Partner. Slough House's cyber expert, Roddy Ho, discovers he cannot hack Hobden's laptop as it is air gapped, furthering everybody's suspicions.
Deputy-Director General Diana Taverner approaches another member of Slough House, Jed Moody, and instructs him to do some "off book" work for her. Two other members of Slough House, Min Harper and Louisa Guy, meet in a pub after work and lament their failed careers. River and Sid decide to tail Hobden, but she confesses that she was assigned to Lamb's team to keep tabs on River. The two see a masked man enter Hobden's home and pursue him, discovering upon entry that Hobden was able to destroy his hard drive with thermite. Hobden escapes as River and Sid fight the masked man, who escapes after shooting Sid in the head.
3
3
"Bad Tradecraft"
James Hawes
Will Smith
8 April 2022 (2022-04-08)
Sid, alive but in critical condition, is taken to hospital by MI5 security operatives who detain River. Lamb breaks him out, and the two deduce Moody was the gunman sent to kill Hobden. Moody returns to Slough House and attacks Min and Louisa when they re-enter, but is killed when he breaks his neck falling down the stairs in a scuffle. Lamb thinks that Slough House is going to be blamed for whatever operation Regent's Park is running and be disowned if it fails.
Taverner meets with Lamb and reveals Ahmed is the nephew of the second-in-command of Pakistani Military Intelligence. His kidnapping and intended rescue is an unsanctioned false-flag operation masterminded by Taverner herself to potentially increase cooperation with Pakistan as well as neutralise and intimidate the far-right. She claims to have an operative embedded with the Sons of Albion who organised the kidnapping but will also facilitate the rescue. It is also revealed that Standish narrowly escaped a treason charge through her links with Partner and his death.
Hobden meets with Judd and tries to convince him to go public with the information that Hassan's kidnapping is a setup, only to be rebuked. Curly is seen making a series of discreet calls with a burner phone, implying he is Taverner's mole. Hassan tries to escape and is threatened by Moe. Giving him a chance to save face, Taverner offers Lamb's team the opportunity to signal to her man the raid is about to commence, allowing him to escape with Hassan. He, River, Min and Louisa arrive at the property but upon entry discover it empty aside from Moe's beheaded corpse.
It is revealed that Moe (real name Alan Black) was Taverner's mole but was found out and murdered by Curly, who then fled with Zeppo, Larry and Hassan. Driving out of London, Zeppo and Larry reveal that they never intended to go through with killing Ahmed and entertain the idea of releasing him, becoming increasingly concerned with Curly's erratic behaviour and rhetoric.
Lamb and his team flee the property before the "Dogs" (MI5 security personnel) arrive, knowing that since the operation has not gone to plan that Slough House will be blamed. River is able to rescue Roddy before he can be taken into custody, but Min and Louisa are unable to stop their colleague Struan Loy from being taken from his home by operatives. Taverner calls Standish several times to flip her allegiance, alleging that Lamb was involved with Partner's death, but Standish remains loyal to Lamb when he comes to extract her. Leaving her house the two are apprehended by James Webb and head of security Nick Duffy, who force them into a car after searching Lamb. En route to Regent's Park, Standish is able to free herself and Lamb after pulling a Glock 17 from her handbag, the weapon having been taken from Moody and placed there by Lamb.
Having discovered the fallout of the failed operation, the Director-General of the Security Service, Ingrid Tearney, pulls out of a State Department meeting in the US and heads back to London, giving Taverner limited time to tie off loose ends. Taverner manipulates Struan into giving false evidence that Lamb was the mastermind behind the false flag operation involving Black, instead of her.
5
5
"Fiasco"
James Hawes
Mark Denton & Jonny Stockwood
22 April 2022 (2022-04-22)
When the team reconvenes, River recalls taking a photo of Taverner covertly meeting with Black whilst carrying out surveillance training. Lamb "returns" Duffy's car to Regent's Park and demands to speak with Taverner, who offers him a way out that will result in him being fired but not charged. She also threatens Standish and says that Sid has died in hospital. Lamb informs her there is a bomb in the car he returned, which allows River to sneak in whilst Duffy's security team investigates.
River confronts Webb, alleging Taverner had him purposefully feed him incorrect intel during the Stansted exercise so he would fail and be demoted, as he had the photograph of her meeting with Black. After locating the photo and evading security, he and Lamb threaten to reveal Taverner's operation to the Director General of MI5 and the press.
Standish and Roddy are able to identify the van being used by the Sons of Albion, as it is linked to a previous cover identity used by Black, and begin to track it. Running out of petrol, Curly announces he still plans to behead Ahmed and die resisting arrest, but Zeppo takes over after pulling a handgun he secretly took from Black's corpse. Hassan tells the group his uncle can offer them money for his safe return. After refuelling, Curly is able to disarm and kill Zeppo, regaining control.
6
6
"Follies"
James Hawes
Will Smith
29 April 2022 (2022-04-29)
Taverner confronts Judd at his home, revealing that calls he made to his far-right contacts after Hobden's visit resulted in Black's death and the mission being compromised. Tearney returns from the US, ordering all loose ends be tied up after Taverner further lies to her about the operation. Curly forces Larry and Hassan to a secluded woodland at gunpoint to carry out the beheading. Larry frees Ahmed and attacks Curly with an axe but flees, which enables an injured Curly to recapture Hassan. Larry arrives at a seaport in Harwich but is shot dead by the "Dogs" on the orders of Tearney, who plant a weapon on his corpse to justify the killing.
Curly prepares to kill Hassan outside what he believes is a Norman castle, which Ahmed points out is actually a folly. Lamb, River, Min and Louisa, with assistance from Roddy, are able to track them to the location. Curly and River engage in a brief shoot-out, before the former is knocked out by Hassan with a rock. The Dogs arrive but the group prevent them from killing Curly.
With the outcome seemingly a success, Roddy tells River that all traces of Sid's name have been wiped from existence, indicating she may still be alive. Hobden is killed by Duffy. It is revealed that Partner was the former Director General of MI5, and officially committed suicide as he was being blackmailed by a foreign intelligence service. Lamb tells Standish he knew and provided the gun, as Partner was a close friend. A flashback reveals Lamb killed him and made it look like a suicide, on the orders of River's grandfather, David Cartwright.
Series 2: Dead Lions (2022)
Long-buried Cold War secrets emerge and threaten to bring carnage to the streets of London. When a liaison with Russian villains takes a fatal turn, our hapless heroes must overcome their individual failings and raise their spy game in a race to prevent a catastrophic incident.
Former field agent Richard Bough, aka Dickie Bow, recognizes and follows a man who tortured him during the Cold War, only to die on a rail replacement bus from an apparent heart attack. Jackson Lamb investigates, finding Bough's hidden phone under the seat with the message "cicada", and gets the team at Slough House to look deeper.
River speaks with his grandfather about Bough's death. David discusses the "cicada" theory of Russian sleeper agents embedded in British society, which MI5 dismissed as a hoax after no sleepers were found and discovered that the programme's alleged mastermind, Alexander Popov, did not exist. He tells River that Bough went AWOL in East Berlin and was assumed to have defected, but returned drunk. Bough claimed to have been kidnapped and tortured by Popov, who force-fed him brandy, but was fired. David dismisses River's theory that Bough's death was the work of the FSB or related to a conspiracy, but warns River to be careful.
Min and Louisa are seconded by Webb to provide background security for a clandestine meeting at The Glasshouse between him and Arkady Pashkin, a representative of UK-based energy oligarch and defector Ilya Nevsky. Ho and newcomer Shirley Dander retrieve CCTV footage from the bus and train, showing that the man Bough was following discreetly poisoned him and then took a further train to Stroud in The Cotswolds. River approaches Lamb, revealing that he knows about the cicada conspiracy and is going to Stroud to pursue the matter further.
Lamb meets with Nikolai Katinsky, an ex-KGB agent and defector. He alleges when stationed in East Berlin that he overheard Popov demanding the cicada program remain funded after the fall of the Soviet Union. His description of the man Popov was speaking to, Andrei Chernitsky, matches Bough's killer. River bribes a taxi driver in Stroud, who reveals he drove Chernitsky to an airfield and flying club in Upshott, but was instructed to lie about it and call a number should people come looking. Ho traces the number, which places the phone in Estonia. Lamb meets with Taverner and convinces her to fund a fake ID and cover package for River, who he then meets and instructs to investigate the airfield and its owner, Duncan Tropper. Taverner is dealing with now-Home Secretary Peter Judd regarding a large upcoming anti-capitalist protest in London.
Webb reveals his planned meet with Pashkin to Taverner, who reluctantly approves despite the UK's agreement with Moscow to keep intelligence operatives away from Nevsky, a critic of the Russian government. Min and Louisa meet with Pashkin's security operatives Piotr and Kyril, but the Russians lie to them about where they are staying. Min covertly follows them back to a commercial address at Edgware Road but is confronted by Piotr, who puts a gun to his head.
9
3
"Drinking Games"
Jeremy Lovering
Morwenna Banks
9 December 2022 (2022-12-09)
The gun threat is a joke, and Piotr invites Min to drink vodka with him and Kyril. The Russians cut the session short when a friend visits, and afterwards Min is killed when supposedly struck accidentally by a car as he is cycling home drunk. Believing he was targeted also, Lamb investigates the driver, Rebecca, and discovers she previously lived in Vladivostok. He confronts her, and she confesses she was paid off. Min wasn't killed by her car, and she was not driving.
Judd is delivering a speech in the City of London on the day of the anti-capitalist protest. For added security, he is to be accompanied by Nick Duffy, leader of the "Dogs", a tactical and security unit, but he demands that Taverner join him instead. Newcomer Marcus Longridge replaces Min on the Pashkin assignment and confesses to Louisa he has a gambling addiction.
Ho, Dander and Standish deduce that Chernitsky never left the UK, and just planted his phone in the luggage of an Estonia-bound touring folk band at the airport. Using his cover as a journalist from The Times, River befriends Kelly, the daughter of the suspected sleeper agent Duncan Tropper. He discovers through her that Tropper and his wife Alex used to be student radicals who moved to the village from London. The family invite him to dinner and introduce him to their visiting friend Leo, who is actually Chernitsky.
10
4
"Cicada"
Jeremy Lovering
Mark Denton & Jonny Stockwood
16 December 2022 (2022-12-16)
Rebecca recounts that Min was attacked and run over by Piotr and Kyril, and finished off by Chernitsky before his death was staged. Lamb discovers Katinsky's involvement as a triple agent; he agreed to assist the Russians and distract Lamb in exchange for facing no repercussions for his defection decades earlier. Standish speaks with Victor Krymov, the intermediary who set up the meet between Paskhin and Webb. Lamb suggests that Krymov lied about Pashkin being Nevsky's representative, with the younger Russian likely being his competitor.
Dander and Lamb visit Nevsky's residence to find him murdered by radiation poisoning. Louisa meets with Pashkin at his hotel armed with a utility knife, intent on torturing him as she believes he is responsible for Min's death. She is stopped by Longridge. Lamb orders her to temporarily stand down and proceed with the meeting, as Pashkin might resist interrogation. He approaches Regent's Park. Chernitsky leaves the Tropper residence and is pursued by River, who confronts him and Katinsky at the airfield loading an improvised explosive device onto a plane. Alex Tropper arrives and explains Katinsky is another friend from university. Then she incapacitates River with a stun gun, revealing she is the sleeper agent.
11
5
"Boardroom Politics"
Jeremy Lovering
Mark Denton & Jonny Stockwood
23 December 2022 (2022-12-23)
After Alex takes off, Katinsky tells River they plan to fly the plane into The Glasshouse. Duncan and Kelly find and untie River, and he is able to convince them of Alex's true identity. River calls in a "Code September", prompting Taverner to evacuate Judd from his speech at The Royal Exchange and the immediate area around The Glasshouse. Lamb blackmails Duffy to get him into the records department at Regent's Park. He deduces Katinsky is the spymaster behind the cicada program (passing himself off as a junior bureaucrat when defecting to avoid suspicion) and was the handler of a traitor in the service. Standish beats Krymov in a game of chess and he reveals it was Katinsky, not Pashkin, who he met with to set up the Webb meeting. Katinsky specifically requested Lamb's team to be involved.
The meeting between Paskhin and Webb at The Glasshouse proceeds as planned. However, an evacuation alarm activates and Pashkin pulls a gun. Louisa explains to Webb that Pashkin is likely FSB and killed Nevsky. Pashkin shoots Webb and escapes with Piotr, locking the agents inside. Longridge shoots Kyril with a pistol he hid in the conference room. Ho and Dander trace Chernitsky to a train station in central London and pursue him as the evacuations take place.
12
6
"Old Scores"
Jeremy Lovering
Will Smith
30 December 2022 (2022-12-30)
Louisa interrogates a dying Kyril and learns that Pashkin and his associates were meant to drain Nevsky's accounts from the Glasshouse while it was evacuated. River discovers the bomb left at the airfield and realizes the attack was a hoax, calling Taverner to have the Code September retracted. Alex diverts her course, defusing the situation once the Glasshouse has been closed long enough for the heist to take place. Ho notifies River that Chernitsky's destination is Tunbridge Wells, where his grandfather lives.
Chernitsky ambushes Ho on the train but, after Dander boards the train and helps fight him, escapes. Lamb calls Katinsky, deducing that he is the supposedly fictional Russian spymaster "Alexander Popov". Katinsky reveals that outside of his part in the Glasshouse plot, he also intended to kill Lamb in retribution for Charles Partner, his mole at MI5. Lamb, already aware of this, had notified David that he was another potential target due to his complicity in Partner's death. By the time River arrives at Tunbridge Wells by plane with Kelly, David has already ambushed and killed Chernitsky with a shotgun. Louisa and Longridge kill Pashkin when he attempts to escape the Glasshouse, having betrayed and killed Piotr along the way. Realizing he has been outmaneuvered, Katinsky goads Lamb to kill him. Lamb instead leaves Katinsky with one bullet left in his revolver, and Katinsky kills himself.
Taverner and Judd create a cover story for the Code September hoax, blaming it publicly on a security glitch and implicating the prime minister, thereby improving Judd's odds against him in the next leadership election. Lamb requests Taverner to place a plaque for Min with other fallen MI5 agents at St. Leonard's Church, but is denied. Lamb and the Slow Horses break into the church and hide a plaque for Min behind a bench. After the rest of Slough House leaves, Lamb adds a handwritten note commemorating Dickie Bow's service as a joe.
Sean Donovan and Alison Dunn are lovers and British intelligence operatives stationed in Istanbul. One night Donovan follows Dunn, suspecting she has stolen a classified file from the British embassy. She loses him during a chase through the city before exchanging the file (labelled 'Footprint') with an unknown man. Donovan soon finds and grieves over Dunn's murdered body. At Slough House, the team are engaged in their usual tedious tasks. Attending her post-work AA meeting, Catherine Standish is befriended by Donovan (calling himself "John" and pretending to be part of the AA group) and they go to a cafe; feeling uneasy after Donovan mentions Jackson Lamb, Standish tries to sneak out but is kidnapped by a team led by Donovan. The next day, the slow horses investigate Standish's unusual absence. Shirley Dander and Marcus Longridge go to Standish's flat and realize she hasn't been home. Louisa Guy tracks Standish's movements to the cafe, notices that security camera cables had been cut, and finds something of Standish's in a nearby underpass. At Slough House, River Cartwright is texted a photo of Standish with a gun to her head and the message "Barbican bridge, one minute or she dies."
14
2
"Hard Lessons"
Saul Metzstein
Will Smith
29 November 2023 (2023-11-29)
Telling no one about the message, River races to the Barbican Bridge and meets James "Spider" Webb, acting on behalf of the kidnappers who have threatened his family. Webb instructs River to steal the Prime Minister's vetting file from MI5 headquarters ('the Park') before midday (an hour) or Standish will be killed. River suspects he is the victim of a prank until a sniper's laser-target appears on Webb's chest. River gains entry to the Park by claiming to have found a missing diamond from the Glasshouse incident in Season 2. Meanwhile, Guy continues to investigate the cafe's surroundings and links an abandoned car to Donovan. Lamb notices Slough House is being watched. Dander and Longridge follow one of the watchers, but he escapes. Lamb meets with an old associate, Sam Chapman, and establishes that Donovan is employed by a private security firm. At the Park, River evades Nick Duffy, the head of the Dogs (security), and gradually works his way into the records department after stealing a security pass from another Dog, Hobbs. Head of records Molly Doran refuses to help River find the PM's file. Lamb calls, instructing River to get out of the Park immediately, saying that Standish is in no real danger because the kidnappers are from a "tiger team" designed to test MI5 security. River sneaks out of the Park but is later captured by Duffy and his team.
15
3
"Negotiating With Tigers"
Saul Metzstein
Will Smith
6 December 2023 (2023-12-06)
River is given a brutal and vindictive beating by Duffy in revenge for having made the Dogs look incompetent. Lamb discovers that Standish's kidnappers are private security firm Chieftain, a "tiger team" hired by Home Secretary Peter Judd to demonstrate weaknesses in MI5's security. Judd uses the operation's apparent success to strongarm Tearney into privatising MI5's security, giving business to Chieftain, who are run by an old school friend of Judd's, Sly Monteith. Monteith loses control of the situation, however, when Donovan goes rogue, kidnapping Chieftain operative Sturges and taking Standish and Sturges to a new safe house. Dander and Longridge break into Donovan's house unauthorised and learn about "stage two" of his plan, which is to get hold of MI5's Grey Books, a record of conspiracy theories. The two report this finding to Lamb, who secures River's release from MI5 and sends him with Guy to Chieftain's headquarters, where they discover that Webb had been working with Chieftain the entire time. Monteith sends Webb to pay off Donovan and secure the release of Standish, but an altercation leads to Donovan accidentally killing Webb. Lamb interrupts Judd and Monteith's dinner at a posh restaurant to try to secure Standish's release. Donovan dumps Webb's body outside the restaurant.
16
4
"Uninvited Guests"
Saul Metzstein
Mark Denton & Jonny Stockwood
13 December 2023 (2023-12-13)
Tearney reasserts control over MI5. She plans to allow Donovan access to the Grey Books in return for Standish’s release and then have him arrested by Duffy. Meanwhile, Sturges escapes from the safehouse, where Donovan reveals that he is working with Alison Dunn’s siblings, Ben and Sarah, seeking justice for her death. Standish sympathises and tells them where they can find the file they are seeking. Meanwhile, Dander and Longridge are fired by Lamb, and River comforts his grandfather, who is suffering from memory lapses. Ho locates the safehouse and sets off with Lamb to rescue Standish. River and Guy escort Donovan and Ben into the file-storage facility, where Ben reveals that the Grey Books were a ruse and that he is seeking a different file. After a conversation with Doran, Tearney deduces that someone in the Park has hidden a particular file inside the facility for Donovan to find. Duffy takes charge of a team of Chieftain mercenaries and is ordered by Tearney to kill everyone inside the facility to ensure the file isn't leaked.
17
5
"Cleaning Up"
Saul Metzstein
Mark Denton & Jonny Stockwood
20 December 2023 (2023-12-20)
Tearney confronts Taverner, who is revealed to have been Donovan's source, and had left the "Footprint" file in the facility for Donovan to leak, as it contains evidence of wrongdoing that will lead to Tearney's downfall. Chieftain operatives prepare to enter the facility and set up a trap outside of it. River warns Lamb and then calls Slough House, asking for the help of Dander and Longridge just before Chieftain cuts off the phone lines. Dander and Longridge arm themselves and drive to the facility, hoping that by helping River and Guy they may be given their jobs back by Lamb. Chieftain agents storm the building and capture Douglas, the facility's sole security employee, who is ruthlessly executed by Duffy shortly afterwards. Lamb reaches Standish at the Dunn house and rescues her from Sarah, but Sturges and Hobbs arrive with orders to kill everyone at the house. River, Guy, Ben, and Donovan resist the assault and find the "Footprint" file, but Ben is killed.
18
6
"Footprints"
Saul Metzstein
Will Smith
27 December 2023 (2023-12-27)
Hobbs and Sturges storm the Dunn house, however are outmanoeuvred by Lamb, who rigs the house with booby traps. Sarah strangles Sturges to death after a brief struggle, while Lamb kills Hobbs. Ho attempts an heroic rescue, crashing a bus through the side of the house, too late to be of any help. Donovan sacrifices himself to allow River and Guy to escape the file storage facility with the "Footprint" file and they are rescued from Duffy’s planned ambush by Dander. Longridge defeats Duffy in a fistfight and Guy finishes Duffy off with a rock to the head. Lamb tells Standish that her hero, Charles Partner, was a traitor who was using her, leading a devastated Standish to resign from Slough House. River takes “Footprint” to his grandfather, who destroys it, worrying about the reputational damage it will cause to MI5. Anticipating this, River already made a copy, which he leaks. In the aftermath, Tearney and Judd are forced to resign, with Taverner assuming Tearney’s place as First Desk.
Production
The series was given a straight to series order by Apple TV+ in October 2019, with Gary Oldman announced to star.[12] The cast was rounded out in December 2020 with the additions of Olivia Cooke, Jonathan Pryce, Kristin Scott Thomas and Jack Lowden. Initially the production was to consist of two series, but three additional series have since been ordered.[3] Each series has been based on an individual book in the Slough House series.
Filming of the first series began on 30 November 2020 in England, and continued into February 2021, with Gary Oldman and Kristin Scott Thomas spotted on set in Westminster, London.[13] In July 2021, filming continued in Stroud, Gloucestershire.[14] It was originally intended to film earlier in 2020 but was delayed due to the COVID-19 pandemic.[15][13]
In June 2022, ahead of the second series premiere, the series was renewed for third and fourth series, which will be based on the next novels in the series, Real Tigers and Spook Street.[3][16]Saul Metzstein has been announced as the director of series 3.[17] As of March 2023[update], filming of Season 3 had been completed and filming of Season 4 was about to begin.[18] Series 4 is directed by Adam Randall.[19]
The title track "Strange Game" was performed by Rolling Stones frontman Mick Jagger, who wrote the song exclusively for the show together with the show's composer Daniel Pemberton.[20]
Reception
The first series received highly positive reviews. Rotten Tomatoes lists a 95% approval rating with an average rating of 7.7/10, based on 60 critic reviews. The website's critics consensus reads, "Slow Horses refreshes the espionage genre by letting its band of snoops be bumbling, with Gary Oldman giving a masterclass in frumpy authority."[21] On Metacritic, the first series has a weighted average score of 78 out of 100 based on 22 critics, indicating "generally favorable reviews".[22]
The second series received critical acclaim. Rotten Tomatoes reports a 100% approval rating with an average rating of 8.5/10, based on 26 critic reviews. The website's critical consensus says, "Slow Horses says nay to the sophomore jinx with a second series that might be even better than its supremely addictive predecessor."[23] On Metacritic, series two has a weighted average score of 84 out of 100 based on 10 critics, indicating "universal acclaim".[24] Oldman was nominated for a Golden Globe and BAFTA Award for his portrayal of Lamb for the second series.
The third series received critical acclaim. Rotten Tomatoes reports a 96% approval rating with an average rating of 8.7/10, based on 28 critic reviews. The website's critical consensus says, "Slow Horses' shabby charms reach a full gallop in this superb third season, yielding what might just be Slough House's most compelling operation yet."[25] On Metacritic, series three has a weighted average score of 85 out of 100 based on 18 critics, indicating "universal acclaim".[26]
