If season four isn’t as good as season three, it’s entirely due to the source material. Real Tigers was, by far, the better story, with more for each of the Slow Horses to do. Spook Street’s focus on River sidelines the rest of the crew, even Jackson.

It’s kudos, then, to Will Smith and his team of writers that they eked as much as they did from the novel, even if some of the changes felt a little desperate (specifically their handling of Sam Chapman).

As I suspected would be the case, the TV series smooths over the sillier aspects of Spook Street. The convoluted reasoning behind Frank Harkness’s operation is simplified. Frank is also given more to do, becoming less the shadowy presence of the novel. This is a good thing because Hugo Weaving is excellent in the role (the only drawback, again a consequence of the source material, is that he and Jackson never meet).

There are other changes*: The climactic battle plays out differently (though the major spoiler** still occurs). The fantastic Molly is also given more to do, though her scenes with Frank are another example of the writers trying to generate tension from a less-than-suspenseful middle section of the novel. A critical scene between First Desk (played, with wet-blanket energy, by James Callis) and Jackson is handed to another character.

On the matter of First Desk, Claude Whelan, the modifications to his character were one of the few divergences I didn’t like. While Claude is clearly out of his depth in the novel, he’s not the bumbling fool we see throughout the season. I get that most of his depth is interior—thoughts about his worth, his wife, and how easily he’s been manipulated—and therefore difficult to translate on screen. I just don’t feel they tried hard enough (the moment when he tries to turn on a PowerPoint presentation is especially cringeworthy).

I did, however, love Ruth Bradley as Emma Flyte. If there’s one thing I’m sad about, it’s that there’s no scene (like in the book) between her and Louisa in a pub bitching about the Park. I also liked Tom Brooke’s Coe, even if he’s given fuck all to do (until the climax).***

The best bit of the series comes at the very end. It’s a scene between River and David (no, I’m not going to spoil it), and it’s entirely original to the show. It hurt my heart.

Given what they were working with, the writers (and I assume the producers and directors) deserve a round of applause for maintaining (almost) the show’s high quality. I look forward to the next season… where, of course, I’ll read the next book (London Rules) before I watch because that’s how I roll, people!

*This is not an exhaustive list.

** If you’ve read the book but have not watched the show, you’ll know what I mean by this.

*** True, he doesn’t do that much in the novel, but he does figure out several aspects of the plot before others do.