Bodyguard creator Jed Mercurio has said some of the fan theories about the conclusion of the show do have “a grain of truth”.

Speculation has been rife about how the BBC One thriller will wrap up in its final episode on Sunday, but Mercurio has refused to confirm whether Home Secretary Julia Montague (Keeley Hawes) has really been killed off.

He told ITV’s This Morning: “We’re all sitting back and enjoying the speculation. It’s great that people have their own theories.

“Actually, I do look at some of the bigger theories and it’s interesting that occasionally there’s a grain of truth.”

Mercurio previously killed off a character played by Hawes in his series Line Of Duty, and he said: “That’s also part of the history, the fact that it happened before makes people swing towards the idea that she must obviously be dead.

“But then there are other things that are in the drama that make the observant people swing towards the idea that possibly that’s a ruse. We’re just sitting back and enjoying the response and the speculation.”

Mercurio did confirm only one ending has been filmed, saying: “There isn’t an alternative ending. We weren’t in a position where we could commit to doing that and shoot it different ways and then edit it different ways.

“We definitely have a conclusion and I think that at the end of it people will know exactly what they need to know.”

Mercurio added that conversations have begun with the BBC about a second series, saying: “We know that people out there are loving series one and there would be an appetite for series two. We’ll just have to wait and see.

“A lot goes into setting up a production. None of those conversations have taken place yet which would allow us to facilitate that production.

Mercurio was full of praise for the show’s other star Richard Madden.

“Richard’s done a fantastic job on this and we’re all so proud of what he’s achieved and so pleased for him,” he said.

“He’s such a hard working actor and such a lovely guy. It’s great that he’s getting all the attention that he deserves.

“If that character survives then we would have to get into a conversation with Richard about whether he would be available to do another series.”

Teasing what viewers can look forward to as the series reaches its conclusion, he added: “I can tell you that the episode returns to some of the very tense action style sequences of the first two.

“There’s lots of action in the last episode and lots of answers to questions that have been in people’s minds these last few weeks. I’m really very optimistic that people will get a lot out of the episode and they’ll get the answers that they’re looking for.”

Previewing the upcoming series of Life Of Duty, which is currently being filmed in Belfast, he said: “What we’re doing in this series is we’re answering some of the questions that were left over from series four and we’re also starting a whole new investigation that will carry through the six episodes.”