Martin Compston says a lot of the Line of Duty fan theories he reads are “absolutely spot on”

The actor, who stars as DS Steve Arnott, has revealed that he keeps a close eye on fan theories to see if anyone guesses what's really going on in the BBC police anti-corruption drama.

"One of the great joys of the job is these theories that fans come up with," Compston told RadioTimes.com and other press in an interview. "And a lot of the time they're absolutely spot on. Obviously we can't 'like' or say it to give it away."

He added: "But that's one of the great things – and think that's one of the reasons why they're holding the show, it's one episode a week and giving people time to do their research and all these podcasts and recaps and that kind of thing."

The actor also admitted he refers back to some of these materials to refresh his own memory about Line of Duty before a new season, explaining: "There was one of the podcasts I actually listened to before we started, just so I knew what the hell was going on. So they're a great tool for us as well."

But even if Compston does spot an accurate fan theory, he has no intention of ruining the surprise for viewers – and he says the team behind Line of Duty relies on fans to avoid sharing spoilers.

That is especially important when a scene has been filmed in a public location, where paparazzi can turn up – and potentially get spoiler-filled photos.

"One of the harder things - it's great that we have such a following, but there's a bit of a circus that follows us now when we film," he said. "And that's quite tough. Just if you're doing a sort of emotional scene and there's five or six paparazzi in your eye-line, snapping snapping snapping, and all you hear is this clicking going on, and then you're very aware of – is there spoilers? Because there are scenes we have to film outside, and you're just - you don't want to give anything away."

He added: "Fans have been a great help. People don't want spoilers. They really want to enjoy the show as it unfolds. So in terms of us giving things away, we're so kind of drilled not to, but I don't even think if we did that people would really throw us under a bus. People really enjoy the thrill of watching along with everybody."

Details about season six of Line of Duty have been kept mainly under wraps, but we do know that AC-12 will go up against a new adversary – DCI Joanne Davidson, played by Kelly Macdonald.

Compston returns alongside Adrian Dunbar (Superintendent Ted Hastings) and Vicky McClure (DI Kate Fleming), with Shalom Brune-Franklin joining the cast as DC Chloe Bishop.

Line of Duty begins on Sunday 21st March at 9pm on BBC One. Take a look at the rest of our Drama coverage, or check out what else is on with our TV guide.