Mike Bartlett had planned a different ending for the second series of "Doctor Foster".
The recent instalment of the gripping drama came to an end last night (03.10.17) after weeks of cliff hangers, but many fans were left disappointed when it concluded with adulterer Simon Foster (Bertie Carvel) being talked out of suicide by his ex-wife Gemma Foster (Suranne Jones) following two years of fighting and their son Tom (Tom Taylor) running away because he couldn't deal with his parents" toxic relationship.
However, the show's writer has admitted the series wasn't meant to wrap like that as he had initially planned to have Gemma and Tom return home and Simon flee the country.
Speaking to the Radio Times magazine, he said: "The ending of the show unfolded as I was writing it. In the plan, he's [Tom] in the car at the end. They go back to her house and get a new kitchen and try to build a life.
"It was only when I went to write it that she goes back to the car and he's not there. But that happened very organically from what he has been through, I think.
"Tom's not a little child any more, he's going to make his own choices. And so hopefully it's one of those ones which you don't see coming but when it happens you look over the whole series and realise this has been coming the whole time.
"I was so involved in Gemma and Simon's story that's all I was thinking about when writing it. It sounds mad, this. But she comes out of the hotel and he's not there.
"That's the moment you look for as a writer, when the characters start telling you what they are doing rather than you telling them."
Despite divided opinions, Mike has admitted there's "potential" for a third series.
He explained: "You can see the ending. Tom's gone. So there's a question mark. In a way that is a question mark at the end. And I think it works as an end to this series and all the things that have been going on. Clearly there's potential there. But obviously there would have to be lots of conversations.
"We need to talk - Suranne and I and lots of other people need to have lots of conversations and we'll see."