It's not entirely clear how long BBC One's hit drama Line of Duty will run, but when it does finish, it'll be on the show's own terms.

Series creator Jed Mercurio recently acknowledged that the police thriller – which returns on Sunday night for a fifth series, with a sixth already greenlit – has "a lifespan" and that he has "some thoughts" about how it'll end.

Speaking to Digital Spy and other press, actor Martin Compston (who plays DS Steve Arnott) elaborated on Mercurio's masterplan: "Ever since series two, we've been recommissioned for two [series] at a time, because Jed's very adamant that he's going to be the one that finishes it.

"So if he doesn't know if we're getting [series] seven or eight, then he will [finish it], because his thing is that he has to give the pay-off for the audience who've stuck with us all these years."

Jed Mercurio on the set of Line of Duty BBC/World Productions

Adrian Dunbar, returning as Superintendent Ted Hastings, suggested that Mercurio had originally planned five series of Line of Duty, but decided to expand the story arc as the show grew in popularity.

"I think he initially had mapped out roughly up to series five, but then, I suppose because it took off in the way it did, he thought beyond that, and he's still thinking beyond that," Dunbar said.

"But he's still managing to hang on to our initial audience and give them all these pay-offs for sticking with the original arc. The original arc still keeps going."

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A few years ago, there were rumblings of a Line of Duty remake in the US. Could this be a way to expand the franchise?

"I think Richard Gere would be a good fit [to play Hastings] – we're very similar in many ways!" joked Dunbar.



Compston, FYI, nominated Tom Cruise to replace him as Arnott "just because of the height", while Vicky McClure named Jennifer Lopez as her top pick to play the new Kate Fleming.

"It's going to be called Line of Booty!" Dunbar quipped. (Be honest, you'd totally watch that show.)

Line of Duty returns to BBC One on Sunday, March 31 at 9pm.

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