Slow Horses creator explains changes from book for season 3

The new season is based on Mick Herron's novel Real Tigers, and tells the story of a conspiracy which envelopes the Slough House gang as MI5 secrets are on the verge of being leaked.

The show's creator, Will Smith, recently caught up with RadioTimes.com about the new season, and revealed how close it sticks to the original source material – and one big deviation it makes.

Smith said: "We try to be as faithful to the book as we can. And certainly, when we do change it, we try and stick to the spirit – we always stick to the spirit of the characters and we're not going to change that at all, because we love Mick’s world and the characters.

"And with the story, it's just building it out. We normally get about four episodes and a couple of really great endings and then we sort of build out from that."

Smith continued: "I think the biggest change in this was... it's all about Sean Donovan seeking revenge for the death of the woman he loves, and it was just showing that death basically, and animating that so it wasn't just a thing that he was remembering, as he does in the book.

Read more:

• Slow Horses season 4 adds Hugo Weaving, Joanna Scanlan and more to cast
• BBC confirms Christmas 2023 line-up: Doctor Who, Ghosts, The Tourist

"It works in the book, because you can go in his head and that's all great, but obviously, you can't do that in TV. And it's just like, if this man is gonna go to these extreme lengths to get vengeance for this woman then, if it's in the abstract and you're only hearing about her you don’t really believe it.

"But if you can see the love they have, you see the grief that that he's experiencing then it explains the things he’s doing, so it was just making sure that you were with him on that journey."

The moment Smith talks about comes right at the start of the first episode, when Katherine Waterston's new character, MI5 agent Alison Dunn, is killed off in a shocking moment.

The other major new character this season, Sean Donovan, is played by Ṣọpẹ́ Dìrísù, who Smith said is a "a massive star, and he's gonna be an even bigger star".

Slow Horses season 3 continues on Wednesday 6th December, while seasons 1-2 are available to watch now on Apple TV+. Sign up to Apple TV+ now. Mick Herron's full Slough House book series is available now.

Check out more of our Drama coverage or visit our TV Guide and Streaming Guide to see what's on tonight.

Try Radio Times magazine today and get 10 issues for only £10 – subscribe now. For more from the biggest stars in TV, listen to The Radio Times Podcast.