'Luther' could come to an end after the next instalment.
Idris Elba
The popular BBC drama sees Idris Elba star as DCI John Luther, and writer Neil Cross has hinted that they may bow out with "one more really big series", although he's unsure what the future holds for the show just yet.
He told Digital Spy: "Idris and I talked seriously about what we wanted to do, and what I can say is that season five is huge.
"It's going to be the biggest we've done. We're really excited by the script, and the story - and Idris and I are very aware that whenever we've done another series, we're like, 'That's it'.
"Idris has a big career. And we leave and then we all start missing it in a couple of weeks, and I start stockpiling Luther ideas and making Luther notes. And we know that we always come back - so we want to come back and do one more really big series.
"What happens after that, we haven't decided..."
The new series is currently in pre-production and will start filming next month.
Meanwhile, Neil and Idris are both toying with the idea of writing a 'Luther' movie.
The show has proven to be a huge hit with TV watchers and Neil has admitted he's found it hard to walk away from the character.
Asked if he still hopes to make a 'Luther' film, he said previously: "Absolutely. The fact is that Idris and I are bound in this shared relationship with this character and every TV [season] we think it's going to be the end, not least because Idris is a very busy and has a successful career but we always miss him when it's over and then I start coming up with ideas and we always come back for more.
"For no other reason than we love doing it. Hopefully in some incarnation, the character will continue."
However, Neil admitted he doesn't specifically know how a movie version would differ from the TV series.
He reflected: "It's always going to be slightly different because of how long you have to tell a story.
"Ultimately, whatever 'Luther' story you tell, in whatever medium, has to focus on that character so in some ways it will be exactly the same because it will be about him."
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