He told the Cheltenham Literature Festival: “The catch-up era has meant that finally the commissioners and executives have come around to the idea that there are people, significant in number, who don’t watch TV casually. They do pay attention.

“They go back, they rewatch, and they actually are substantially involved in driving the success of returning series. So the technology that exists now is a dream for content creators because it means you can return to things from two or three seasons ago, you can bring back characters, and you know the audience will go back and rewatch.”

Mercurio’s latest project is a graphic novel co-written with Prasanna Puwanarajah, an actor who appeared in his 2018 Sky television series Critical. He said he was happy that the book would get a relatively tiny audience in comparison to the millions who tuned in to Line of Duty.

“TV is a mass appeal art form and there are certain types of programme where, if it doesn’t get the audience, it’s considered unsuccessful,” he said. “But having a really intense relationship with the reader is really rewarding. I don’t think something needs to be read by millions of people to be rewarding.”

The finale of the sixth Line of Duty series earlier this year appeared to draw a line under the show’s long-running storylines.

But asked by an audience member whether a seventh series was possible, Mercurio replied: “We would love to do more but at the moment the pieces of the puzzle won’t come together. It would be great if it could happen, but at this point we can’t confirm that it will.”