Summary

• Slough House is filled with a mixture of rejects, misfits, and misunderstood characters.
• Despite their issues, the team frequently proves themselves surprisingly capable in the field
• Understanding the flawed but capable of Slough House is crucial to unpacking the wider Slow Horses story.

Throughout Slow Horses, several disgraced agents have darkened the doors of Slough House, with some having more successful careers in exile than others. Although the outpost is designed to be a purgatory for MI5 operatives deemed too innocent to fire and too useless to hold any real responsibility, the team still manages to find itself embroiled in a number of thrilling and dangerous cases. Given the various characters' reasons for being at Slough House and the stakes often involved in their missions, this situation has dire implications for public safety.

Slough House is overseen by the grizzled, flatulent, and surprisingly effective wider Slow Horses story.

1 Jackson Lamb

Played by: Gary Oldman

The slovenly, rude, and brilliant leader of the Slough House crew, Jackson Lamb is a complicated and contradictory character. Having requested the post after an operation to murder the former first desk Charles Partner, following the latter's defection to the Soviet Union, Lamb spends his time drinking, smoking, eating Chinese takeaway, and abusing any of his colleagues that he comes into with.

However, for all his many, many faults, Lamb retains a keen eye for detail and an almost unparalleled ability to play the strange games involved in spycraft. Throughout Slow Horses, Lamb is almost always several steps ahead of his colleagues and is proven capable of manipulating people and events to suit his agenda. Despite his declared nihilism, his mask occasionally slips to reveal genuine affection for his underlings – especially Standish, whom he goes out of his way to protect.

2 River Cartwright

Played by: Jack Lowden

An earnest, dutiful, yet fundamentally inadequate spy, River Cartwright mixes determination and occasional flashes of brilliance with an inability to navigate the Machiavellian world of MI5. Following in his grandfather's footsteps, River finds himself in Slough House after public humiliation during a routine training op. While it later becomes clear that elements of the operation may have been manipulated to ensure River's failure, subsequent events also suggest that he is not – nor ever will be – the polished agent he would like to be.

Unlike the more cynical of Slough House, River is shown to be genuinely kind-hearted, struggling with some of the more ruthless elements required in the job. His burgeoning relationship with Sid Baker in season 1 and friendship with Louisa Guy prove that, despite his irritating entitlement, he is a deeply caring person. He also can be an effective operator in the field, although consistent high-profile mistakes (like the accidental Code September in season 2) mean that he'll likely never rise as far as he'd like in MI5.

3 Catherine Standish

Played by: Saskia Reeves

Behind Lamb himself, Standish regularly proves herself to be one of Slough House's most capable operators. Ostensibly working as the building's office , she is also very capable in the field, variously interrogating suspects, expertly negotiating terrifying hostage situations, and tracking down terrorists throughout Slow Horses seasons 1 to 3. However, like everyone at Slough House, Standish is also flawed. A recovering alcoholic, she retains an almost fanatical loyalty to her ex-employer, Charles Partner. This leads her into direct conflict with Lamb, who is frustrated by her inability to see the truth about her old boss.

4 Louisa Guy

Played by: Rosalind Eleazar

Sent to Slough House after a tailing operation ended in disaster, Louisa Guy is one of the most traumatized of the team. Initially frosty towards her colleagues, she starts up a relationship with Min Harper – ending in heartbreak when Min is murdered in Slow Horses season 2. This sends Louisa into a personal crisis, not only prompting her to seek revenge for Min's death, but also causing her to steal a diamond in the season 2 finale – a situation that is yet to be fully resolved. Despite her struggles with Min's death, Louisa has formed a firm friendship with River, with the pair proving a formidable partnership in season 3's shootout.

5 Roddy Ho

Played by: Christopher Chung

An incredibly talented but endlessly obnoxious computer expert and hacker, Roddy Ho is a source of huge frustration for his Slough House colleagues. Oozing superiority, Roddy can't help but rub people up the wrong way. In fact, while he is technically one of Slough House's most capable operators, his personality has been his main obstacle in progressing further within MI5, with other characters aware that the only reason he remains a Slow Horse is the rest of the agency's refusal to work with him. However, for all his faults, Roddy has still shown himself to be occasionally courageous, playing a key role in the field in both seasons 2 and 3.

6 Shirley Dander

Played by: Aimee-Ffion Edwards

A field operative who struggles with both anger management and addiction issues, Dander encapsulates the dysfunction on display at Slough House. Although she is proven to be more capable than many of the team, fighting Andre Chernitsky in season 2 and taking on an entire team of mercenaries in season 3, Dander is also her own worst enemy – even getting fired by Jackson Lamb for being found at a crime scene with narcotics. As of the season 3 finale, she has formed a tentative partnership with Marcus Longridge, with the pair helping to moderate each other's worst tendencies.

7 Marcus Longridge

Played by: Kadiff Kirwan

Despite being offered the opportunity to Duffy's unit of "Dogs", Marcus Longridge finds himself at Slough House after struggling with a gambling addiction. Although he, like Dander, is capable in the field, his gambling proves to be a major obstacle, with his attempts to hide it from his wife a source of major tension. He has played a key role in multiple Slough House operations, liaising with Louisa Guy in season 2 and Dander in the explosive season 3 finale. He also kills Nick Duffy in a dramatic season 3 showdown, proving that he is one of the most dangerous current of Slough House.

8 Min Harper

Played by: Dustin Demri-Burns

A bumbling and fundamentally gentle member of the team, Min Harper was relegated to Slough House after accidentally leaving a dossier of top secret documents on a train – a mistake that reveals much about his personality. Although he struggles to get over the blunder (which ultimately led to divorce from his wife), he finds solace in a new relationship with fellow Slow Horse Louisa Guy. Tragically, their time together is cut short when Min Harper is dramatically murdered mid-way through season 2.

9 Sid Baker

Played by: Olivia Cooke

The source of Slow Horses' biggest ongoing mystery, Sid Baker ed the Slough House team in unusual circumstances in season 1. While other are generally assigned to Lamb's crew because of a professional mistake, Sid seems genuinely capable in her job, with there being little indication that she is anything less than a good agent. Unfortunately, she is hospitalized before she can reveal how she really arrived at Slough House – with the mystery only deepening when she is removed from hospital altogether and her identity expunged from the records. Despite not being seen since season 1, Sid's fate remains an unresolved issue.

10 Jed Moody

Played by: Steven Waddington

A former member of the Dogs, Jed Moody plans to escape the confines of Slough House by betraying Lamb and working for Diana Taverner in season 1. Although he hopes his allegiance will see him reinstated, his hopes come crashing down when he is accidentally killed by Min and Louisa when they come back to the office after an evening in the pub. As such, Moody is not seen again after the early episodes of Slow Horses season 1.