Unforgotten writer Chris Lang on revealing Jimmy’s killer: “I don’t think people saw that one coming. I didn’t”

SPOILERS! The creator of the ITV drama talks to Kasia Delgado about changing the culprit, the real-life stories that inspired the plot, and his interest in ordinary people doing terrible things

After the final episode of Unforgotten, one of the best dramas this year, questions were zooming around the brains of viewers who were shocked by the revelation of Jimmy’s killer. As DCI Cassie Stuart (Nicola Walker) and DS Sunny Khan (Sanjeev Bhaskar) finally discovered who murdered the victim, forty years earlier, it was not at all the person most of us believed it would be.


So RadioTimes.com spoke to the show’s screenwriter, Chris Lang, to get some answers to our questions about the final episode, how he wrote the plot twist and how the news inspired him to write about a historic murder case. 

When did you get the idea that you wanted Claire to have done it. Was that always the plan?

It wasn’t, no. In a few dramas I’ve written before I’ve changed at quite a late stage who I want to do it — because if you trick yourself as a writer it means you don’t consciously signal to an audience who it is. Six months of the process it wasn’t her and then I wrote a draft of episode six, and we discussed it with co-execs and the production team and it wasn’t quite singing.  I sort of knew what they meant and I went away and suddenly thought, “actually I know what to do.” It all worked and I knew that it would be a big surprise for everyone because I don’t think people see that one coming. Because I didn’t.

I definitely thought it was Eric. Was he your original culprit?

Exactly. I’d written the drama as if it were him. I never wanted to do a great big reveal. It was always my intention that the drama was just as much about what happens after the guilty party is found, so actually I didn’t think we needed a big reveal. I was happy to play the last two episodes with us knowing it’s him. But actually we changed it because it’s a more interesting back story, it’s a more interesting guilty person, and I could ask, “what do you do when someone who has dementia is found guilty of a heinous crime?” You can’t prosecute them. Just at that moment I had that thought, the Greville Janner case came up and I thought, “yeah this is quite zeitgeisty actually”.

Given its prevalence in the newspapers, were you very careful about approaching the subject of postpartum depression or psychosis with Claire’s character?

We’ve all read the most appalling stories of mums who have had postpartem psychosis where they tragically kill their children and then themselves. I’ve read a number of cases of those over the years, I’ve got personal experience of that illness and I know other people who have had post natal depression so it’s an area I was interested in. And again, it’s another one of those stories where you can understand what happened, it doesn’t diminish the severity of the crime, but you’re trying to understand and not demonise people and say they’re monsters. 

What prompted you to write a drama based on a historic case? It’s quite unusual to go back that far.

Going back 40 years was something a little bit different and it was certainly prompted to a degree by the historical cases that we’ve been reading about in the last two, three or four years. I just thought that would be very interesting territory, that gap between committing a crime and being investigated and then prosecuted for it. I thought, “wow some of these people have lived 50 years getting away with something pretty serious and how did they do that, how did they live their lives without that showing in some way?” 

With Claire, it’s difficult to know how to feel about someone who did something terrible so long ago when she was so ill.

I wanted it to be messy and difficult, not a neat resolution. I was also just interested in the idea of how much you can forgive people for all they’ve done. Some forgive more and some forgive less, some forgive themselves and some don’t at all. Trevor Eve’s character (Sir Philip Cross) doesn’t forgive himself at all. 

 In Unforgotten, all the people who did terrible things were actually just sad and very human. Often in dramas you get a sense of triumph when the killer is found and locked up but that wasn’t the sense here. 

Absolutely, because I think ordinary people can do very bad things but it doesn’t necessarily make them bad people. We’re incredibly quick to judge people and label them as monsters but actually they’re human and fallible and they make sometimes some terrible mistakes, but that doesn’t mean we shouldn’t endeavour, without wanting to sound too pious, to find compassion in ourselves and try to forgive people and allow them to make mistakes and move on.

Some of the families in Unforgotten do that more easily than others. I always wanted all of the characters to be likeable in some way. I think if you make characters too dislikable I think it’s hard to identify and to go on their journeys with them. I wanted people to see themselves in them.

 Matt Slater is left in the care home with his mum and clearly he’s being abusive. Why did you want this cycle of abuse to continue?

I wanted to show two sides to the story — a son who could deal with it to a degree and move on, and a son who completely couldn’t. I’ve got brothers and sisters and we know we view our families in very ways and sometimes you think, “my God, how did these two come out of the same womb, because they have completely different perspectives on life.” Matt is almost completely unable to deal with what he feels he’s been left with. I drew on some of the stories I’d read about Harold Shipman’s son and the shock and horror at having discovered his father is the most prolific serial killer this country has known. How you deal with that is a very personal thing and I wanted to explore that. 

Cassie, unlike other detectives on TV, didn’t have a really tortured home life and she wasn’t battling personal demons. Why did you write her as an ordinary woman?


I was bored of coppers with a drink habit or a mental illness. That was, in a way, an easy get out to make them interesting. I find it much more interesting when people don’t have all of those hangups and still life is difficult and complicated because it’s just is like that, and you can find really fascinating stuff in the minutiae of life. Her dad going through some difficult stuff and her relationship with her son — we see one, we don’t see the other — brings up some questions. It’s how life really is.