*Warning - contains major spoilers for Slow Horses season 6 episode 6.*
The sixth season of Slow Horses was hardly one to pull it punches, with a number of major characters dying across the six episodes.
Paul Higgins's Struan Loy, Jonathan Pryce's David Cartwright, Tom Brooke's JK Coe and Ruth Bradley's Emma Flyte were all killed in the new season, as were new villains Jim and Jane, played by Kyle Soller and MyAnna Buring. Meanwhile, River's fate was left up in the air, as Jack Lowden's hero was poisoned in the season's final moments.
It was therefore a surprise to many book readers that a change was made to the source material, one which saw a life spared.
The character in question is Frank Harkness, River's villainous, mercenary father, who at the end of the season skulked away back into the shadows, after saving his son and sitting down for a conversation.
In Mick Herron's book, Joe Country, it is stated that Frank was killed, even if some readers have theorised that this could have been faked.
Now, speaking exclusively with Radio Times, Roddy Ho star Christopher Chung has suggested that Frank's survival is because the writers "always like to keep their options open".
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He continued: "I actually don't know where that decision specifically came from. Mick has a bit of consultancy within the writers' room, so I don't know if that's something that he wanted to put in just in case.
"I only had a couple of scenes with Hugo this season, or where we were in a similar vicinity. But I was thrilled because I didn't get to work with him in season 4, so I'd love to have him back in the show. I'd love to have them all back. We haven't had a bad cast member on this show, so anyone that wants to come back is more than welcome in my books."
Frank has yet to return in the novels, so Weaving's reappearance in the currently confirmed seventh and eighth seasons of the show would be a surprise. However, Joanna Scanlan's Moira didn't feature in the plot of either Joe Country or Slough House, yet she still returned for season 6.
In the twisting-turning world of Slow Horses, it seems that anything could happen.
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