Line Of Duty series 4: creator Jed Mercurio interview

If I were ever to find myself alone in a room with a dead body I’d created in self-defence and pondering my next move, “plead guilty to manslaughter,” Jed Mercurio tells me. “For the minimum three years sentence. If you take the risk of fighting a murder plea with self-defence and you fail, then you will be convicted of murder and that is a mandatory life sentence.” Getting off with self-defence is really, really hard, says Mercurio, really hard. “I did the research.”

It’s good advice, if alarming in the context of a DVD release-plugging interview. As a general rule, interviewees are more likely to give dully dutiful praise to their collaborators than legal guidance on how best to proceed in the event one should accidentally commit murder. Line Of Duty creator Mercurio is an exception. You’d expect him to be; Line Of Duty is exceptional.

Series four’s move from BBC Two to BBC One has paid off. Over 9m in consolidated ratings watched the penultimate episode, a significant rise compared to the previous three series which grew steadily via word of mouth and critical acclaim.

I’m keen to get the figures right talking to Mercurio because he’s a precise thinker. He knows statistics and trends, and is particular about differentiating between anecdotal and substantive evidence. Whatever calculation you care to make, Line Of Duty is riding high. A fifth series was commissioned last year and will likely arrive in 2019. The mysteries of series four—who is Balaclava Man? Is Ted Hastings true blue?—embedded into our collective brain in a way other crime dramas must dream about. Between ratings, reviews and social media obsessions, (despite a baffling absence from this year’s Bafta nominations), Line Of Duty couldn’t be performing better. Or as Mercurio puts it, “We’re in a fortunate position right now.” That’s roughly as giddy as he gets.

Not that Mercurio isn’t extremely grateful for the show’s success or takes it at all for granted. He clearly is and doesn’t – the reason this series didn’t have an extended length last episode like series three is because he assumed the move to BBC One would make it impossible. “I thought, well, there’s no way we could have a ninety minute finale again because the only way we could do that with the BBC News At Ten is if we went out on a Sunday night—and they’d never put us out on a Sunday night!” he laughs. Line Of Duty series four went out on a Sunday night.

To mark the release of series one to four on DVD, we chatted about the show’s relationship with its audience, the characters of SI Ted Hastings and DCI Roz Huntley, red herrings, attention to detail, the ease at which corruption can spread through institutions, and the colour of stuntmen’s eyebrows…

Earlier today, on This Morning with Phillip Schofield, you said…

[Laughs] You were watching that?! Don’t you have a life?

This is my life!

[Laughs more]

You said, about Maneet [PC Bindra played by Maya Sondhi, a fan favourite revealed in series four to be leaking information to AC-12’s enemies] that “we owe it to the audience to tell them more”. As a writer and director, what is it that you consider you do and don’t owe your audience?

You owe the audience the effort and thought that you put into the work, to make it the best possible piece of work that it is. Also, if people are engaging with the thing once it’s been completed—if they’re not only watching it but they’re watching it week in, week out and they’re talking about it and driving interest in it—then you have to engage with the things that they’re talking about. If people are reacting to characters and saying ‘we want to know more about this character’ or ‘we want to know more about this story’, you at least have to take that on board. If, in the end, you decide that it’s not that worthy of exploration or doesn’t take you anywhere interesting or revealing, then fine, but you at least have to explore it in the first place.

I’d always imagined you as being pretty immune to fan pressure, if that’s the right word for it. You’ve often said ‘there’s no commentary on the scorecard’ – that you prefer to judge the success of the show on ratings and Appreciation Index figures, so I assumed that meant you were less interested in reviews and Twitter obsessions and so on.

“There’s no commentary on the scorecard” is just kind of a motto in life, really, and that relates to a lot of the stuff that surrounds the job I do – whether you’re in favour one week or you’re out of favour, whether you’re up for an award or you’re not up for an award, all of that. In terms of the cold, hard numbers, those are things that go beyond commentary, so at least you can say that is an objective view of how successful a show is being.

Then in terms of what people are talking about, I am interested in what people have to say about the series. That doesn’t mean I’m moved by it or convinced by it or bothered by it or uplifted by it, but I think it’s part of the relationship with the audience. Social media has allowed people to have their say. If you choose to engage with it, then you have to engage with it in a professional way and the only professional way of engaging with it is if someone says something you think illuminates the way in which your programme is being watched.

All of which brings me to the question of Ted Hastings. To me, he’s unimpeachable, you won’t be able to shake my faith in that character no matter what you do—and I’m not presenting that as a challenge! But when it comes to raising questions over his probity, I have the impression you wouldn’t be vulnerable to pleas from people like me not to make Ted a villain. You wouldn’t mind breaking the nation’s heart in service of story?

That’s probably true, yeah. I think that the story has to work. I have to approach the story feeling that I have an understanding of where the audience’s starting point is and their understanding of what Ted Hastings’ values are and where they place him on the moral spectrum. Then I can start moving them in a different direction.

About moving our view on Ted’s morals in a different direction, take the line in the series four finale when he calls Roz Huntley “that wee witch” – would you say Hastings has a problem with women, that Huntley was on the money bringing that up in the interview?

It was intentionally a grey area. It divides viewers in the way that maybe a lot of portrayal of sexism in contemporary drama doesn’t. It’s very easy to show overt sexism where everybody knows that it’s crossed the line. In the modern workplace, sexism has adopted a more subtle persona, therefore people can be accused of sexism where it’s far harder to determine whether they’re actually committing sexism or thinking in a sexist way. I wanted to put Ted Hastings in that position. If your definition of sexism is that to use non gender-neutral language is to be sexist, if you adopt that definition then you have your answer. I think that Hastings’ view would be that he doesn’t believe that non gender-neutral language is sexist in itself.

Ted’s from a different era, isn’t he? Hence his reference to Pan’s People earlier in the series…

That was a cultural reference that was appropriate to his age. In terms of how he conducts himself in the workplace, he is the boss and people are often intimidated by bosses. Possibly, female colleagues haven’t said to him in the past, ‘I’d really rather you didn’t call me darling, however neutrally you’re saying it’.

Talking to [Ted Hastings actor] Adrian Dunbar about it, he felt it was something that the character possibly would do and he would be shocked by someone thinking that it was sexist. I think it’s about finding that grey area.

Ted’s idioms like “now we’re sucking on diesel”, do they come from Adrian, him being a local lad?

That particular one did, yeah. Some do and some don’t. What happens is Adrian will say something and that gets put into the script at a later point. There is a desire to keep him idiomatic in line with his background.

Those phrases are key to the attraction of the character. I remember writing once that Ted’s bilingual – he speaks both police and human. In the middle of all the jargon, he’s our translator, he’ll say “you hoodwinked them” and all of a sudden, we understand what’s going on.

I think you’re right. It’s part of making those scenes transparent to the audience. You can have chunks of jargon that are opaque but what you can’t do is keep the audience out for any length of time, you have to let them in at points to understand the to and fro of the dialogue.

When was the last time you watched, or re-read series one?

I don’t think I’ve seen it since it went out.

You didn’t go back to those scripts while writing series four?

I might have gone back to look something up that I didn’t have at my fingertips, but I didn’t re-read the scripts and I certainly didn’t re-watch it.

The reason I ask is to do with the Hilton and Hastings lunch scene in the series four opener and that in series one. Those scenes feel to me to me very much of a pair.

They were. I remembered the series one lunch scene very clearly, shooting it in Brindley Place in Birmingham in a particular restaurant that was quite near my flat. I remember the scene reasonably well. Actually in the scene in series four, there was a bit more dialogue between them that we trimmed down to keep the pace of the episode up, but there were things you could take as referring to the previous lunch about who got the bill last time and stuff like that.

What else was written and/or filmed that didn’t make it into the series four episodes? Did you write any more scenes for Hilton after he was unveiled, for instance?

There were never any scenes of him on the run. There was a scene in the last episode between him and Jamie that we didn’t include. That was just going to shed more light on the way in which Hilton was manipulating Jamie and using Jamie’s bitterness towards AC-12 to make him do his bidding. It made it clear that Hilton was appearing to Jamie to be asking him to do things that were legal and in service of an anti-corruption investigation, but it was actually Hilton’s scheme against AC-12 to maintain the cover-up.

We try and shoot a little bit more material than we have for the running time just so we never get in a situation where we have a significant under-run. Unfortunately it was a small scene that didn’t make the final cut.

If you’re following the online responses, there must be some frustration when people have questions about things—for instance, Jamie and Hilton’s relationship, when it began and how long Jamie’s been a Hilton plant and so on—and you know that you had footage that answers those questions but haven’t been able to show it?

Yeah, but then, in the edit, you have to have those questions for yourself anyway. You have to ask whether the story is becoming opaque or incoherent by the omission of this scene and if it is, then you’ve got to put this scene back in and take something else away. That’s always a process. In the end, you have to come up with the best judgement about how important a point is.

I think we all felt there were enough clues in the dialogue when Jamie says “Hastings didn’t appreciate my ability, Hilton does”, you got the sense that there must have been a conversation at some point between Hilton and Jamie in which Hilton said ‘You’re the right type of young lad, you’ll go far, I’ll set you up in AC-9 and we can make sure people like Ted Hastings don’t get their own way the whole time’.

The series relies on us filling in gaps like that, which obviously we do as we’re a very engaged audience, you’ve made us one. Take a character like DS Neil Twyler [Mark Stobbart]. How much effort goes into making him look potentially dodgy in early episodes to create suspicion? Or are we just in such a frenzy at that point that we’ll suspect anyone without even a nudge and are doing that job for you?

You’re doing our job for us! There’s nothing dodgy about Neil Twyler [laughs].

That’s about the way in which people watch something when they know they’re watching a crime drama. They start regarding everybody who is part of the cast as being someone who potentially could relate to the crime, otherwise why would they be in the series? It’s like that Brian Clough quote about the off-side rule “If you’re not interfering with play, what are you doing on the field?”

So then, tell me, did I imagine the camera—because this was in one of the two episodes you directed—lingering on Nick Huntley’s empty car boot just for a second after we’d watched Balaclava Man bundle Hana Reznikova into his car boot a few scenes before?

That was intentional. It was intentional. Two things about that were intentional. The first one was that the shot of Nick Huntley’s car arriving on the drive was shot from the same high angle with the same framing as the shot out of Tim Ifield’s flat window of the car pulling up outside, so that you would have the maximum chance of making the visual connection between the two. In respect of the boot, yes, it was a deliberate decision to shoot into the boot to show him taking the case out and seeing the empty boot.

By the way, you know you’re going to be responsible for a spike in Marion And Geoff DVD sales after that reference from Kate in the finale?

That gag just occurred to me as I was writing the dialogue. It’s Kate’s view of what Nick was doing sitting in his car outside like Rob Brydon in [BBC mockumentary Marion And Geoff]. It just occurred to me as a gag and it kind of got through so many drafts that we ended up leaving it in.

I like to think Kate’s just a huge nerd about late nineties British alt-comedy. She’s big into Brass Eye…

[Laughs] Yeah, Spaced, all that.

So it’s half we’re in a frenzy of suspicion watching a crime drama then, and half that you’re leading our suspicions with details like that then.

It’s a relationship. It goes back to the first question about what we owe the audience. I consider it part of my job to understand as much as possible about how people watch the series and how they respond to it. Also, if you linger on something then it has a value. It just makes practical sense to shoot that stuff and then make the decision in the edit whether it’s that important.

Later on, when Nick is potentially linked to the abduction and murder of Leonie Collersdale, anyone who goes back will see that he’s absent at the time of Hana’s abduction, we don’t know where he is because we never see him.

His meeting overran, he told Roz.

That’s it. And then we see the boot of his car as if he’s had something in the boot at some point.

We still don’t know quite what Nick was doing on November the 25^th, do we?

Well, we do. He was at a conference in Northampton and then he drove home. He drove up the motorway, he claimed he was still there late so that he would have an alibi for the Balaclava Man photograph on the 25^th but actually he went home but had no alibi. Presumably he got home to an empty house and no-one can vouch for him.

At what specific point did the ‘H’ device occur to you? All the way back in 2012, naming Hastings “like the battle”, Hilton and Hargreaves, were you already planning to make use of it, or did the lightbulb moment that you could connect them all come in writing series four?

It was something that occurred a little bit later. Certainly, the point where Dot tells Hilton in series one in the car park outside Kingsgate Station that when he was a young lad, he was a caddy in the local golf club and someone showed him the ropes, he’s effectively saying to Hilton that he’s The Caddy. At that point, there was always an idea that Hilton could come back at some point and point the finger at Dot, or that he could actually be complicit in Dot’s work as The Caddy. It was really a matter of time.

When we started doing series one, we had no idea that we were going to even get a series two, so you could end up doing something where it gets so bogged down in red herrings stored up for the future that the drama has no forward momentum. I think you have to be very careful with that, and it’s only when you get into the fortunate position we’re now in, and we are in an exceptionally fortunate position now, that you can be a little bit more self-referential and pick up on these things and create a meta-narrative that doesn’t get in the way of the main narrative story.

You’re writing for two audiences, those who’ve watched from the start, and those jumping on at series four. With the early series on Netflix UK as well, you must have seen those audiences merge – newcomers are watching the episodes live then going back to catch up on the previous ones while series four is still on.

We also know, anecdotally, that people watch the episodes more than once. We’re quite intentional in being quite dense with the storytelling and when we do get a note that maybe we should repeat something or plot something out a little bit more slowly so that we see more of the stages, we think, well, so far we haven’t done that and all the data we get back from our audience research is telling us that we’re getting it right. In that way, I think we just have to have the courage of our convictions.

You also know that people like me – as you say, I don’t have a life – are going to watch the episodes with a freeze-frame button and screengrab software.

[Laughs] I think that actually transitions into having a life! I think it’s that middle ground that’s the problem. If you’re actually going to take it that seriously, then you’re back into having a life, that’s the proper direction!

[Laughs] That freeze-frame knowledge must affect things in the edit. I had whole debates with people, in real life, about the colour of the eyebrows of the stunt double in the scene where Steve is thrown down the stairwell. Long debates. This is the madness you’ve foist upon us!

We have those same conversations on set! In fact, Make-Up did some work on [the stuntman’s] eyebrows and then we did some work in post on that.

Actually, when Hana was abducted—I’ll tell you this—when Hana was abducted we used the stunt guy who was inside the Balaclava Man costume to bundle Hana into the car as it drove off. I also got Scott Reid who played Michael [Farmer, the man falsely charged with serial murder] to do exactly the same action and we shot that as well.

Did we see that?! Did you end up using shots of Scott in that scene?

We didn’t use any shot where it came onto his face. There was a little bit that was his arm. We did lots of coverage of Scott. It was one of the last things we did on those night shoots – it was about five o clock in the morning and Scott just came down for the last bit so we got a bit more coverage and got those shots on him.

I was just concerned that someone might say ‘This obviously isn’t the same guy’ because he walks differently or his shoulders swagger in a different way, but then when we looked at it in the edit and showed it to people, nobody could tell the difference so we were alright.

Believe me, you couldn’t tell. I tried!

We have to talk about Thandie Newton as your lead this series. Her performance as DCI Roz Huntley was extraordinary for its… composure, I think that’s the word. I gather when you directed her the notes were all ‘do less, give away less’. She kept that unreadable Renaissance portrait-like mask almost throughout.

Unreadable is often what it says in the script, [laughs] not in the sense that the script’s unreadable but in the sense that her expression is unreadable!

The idea I suppose is always to have us asking ourselves questions about her.

Yeah.

The other effect is that on the very few occasions her emotions do get the better of her, we were even more alert to them and they meant a great deal more.

I wanted her to be a blank canvas so that we wouldn’t always know what was going on and we’d have to try and figure out around her actions. Like she says to Nick, “Don’t listen to what I say, look at what I do.” It is a powerful way of showing character. You can have characters that say one thing and do another, and in certain kinds of drama you can’t get away with that because the audience will become confused—or certainly, the commissioners will become confused and tell you to stop doing it! Whereas on Line Of Duty, we do that all the time, we constantly show people brazenly lying and don’t give any clue to it. We rely on the fact that the audience will pick up on the fact that they’re giving a different version of events so I have to trust that they’ve identified that they’re lying.

That emotion is also part of her journey. What I was saying to Thandie is that this was really hard work for Roz, to keep all these secrets and to juggle all these balls all the way through, and eventually, she’s going to get so frazzled by it, she’s going to make mistakes and she does. She mishears the item reference for the forensic evidence, she doesn’t get her wound dealt with quickly enough, all those things end up gathering momentum against her.

The wound – obviously, the MRSA was a plot point key to her being charged—but as a writer the imagery of that festering rot underneath everyone’s noses must have really appealed in terms of metaphor.

The idea of a physical stigma is quite appealing. When I wrote the book of Bodies, there was a lot of that in the book about how there are physical manifestations of psychological problems—I think it’s described as ‘Narrativizing The Body’. It’s the idea that someone would be carrying a stigma of a foul act that she’d carried out and that this thing itself becomes foul, and the only person who smells it is her husband. It’s there for her but it’s also there for the audience.

We sometimes create a pact between the antagonist and the audience, and maybe with the pace that we run at, sometimes the audience forget that they’re the only ones who are in on certain things so they start thinking ‘But aren’t the detectives aware of this? Aren’t AC-12 aware of this?’ The way it’s been constructed though, the audience is ahead of AC-12, or certainly was in series four and also in series one. In series two, we made the Lindsay Denton character so enigmatic that the audience never knew.

When Kate judged Huntley to be a “boring suburban mum”, she was pretty far off the mark, wasn’t she?

I think that’s probably the way that Kate sees her. At that point, Roz is a career DCI who appears to be happily married and has two kids. Though we don’t necessarily see those things, one can imagine that she talks about having to leave to do the school run or taking a call from one of her kids in the middle of something and she’s doing that thing of ‘Have you looked in your coat pocket?’, all that kind of stuff.

Kate, who is someone who hasn’t embraced the whole idea of conventional motherhood and being part of a family, is saying that in a way that is genuinely her world view. Kate thinks she’s a bit more rock and roll than Roz.

At home, Roz is often doing housework, she’s always picking up dirty washing. Perhaps that’s just a bit of realism with teenage kids in the house!

In the first scene in the house when Nick comes in to find Roz and there’s a towel slung over the thing and with annoyance he picks it up and flings it into one of the kids’ rooms, that’s just part of the texture of domestic life.

In respect of the particular scene where she was doing laundry and Roz and Nick were talking, the director John Strickland had that idea as a way of keeping the scene dynamic rather than the two characters just standing in a room talking to each other, he had the idea of creating all that movement.

We weren’t supposed to draw any ponderous metaphorical conclusions from that then – that she’s always trying to wash dirty things clean…

A lot of the time in the script she was doing domestic chores. The first time we see her she’s unloading the dishwasher. All those things were in the script. In that particular scene, I’d written it much more simply that she was loading the washing machine, that’s where the conversation takes off but John felt there was a way of showing her bringing the laundry basket down the stairs and going to the washing machine that just made more of an issue of it.

I’m interested in how you allowed Huntley a couple of redemptive moments at the end—she confesses, she gets Lakewell, she helps to convince Jamie to drop the gun—just as you did for Dot with his jumping in front of Kate’s bullet and his dying declaration. Jimmy Lakewell and Hilton didn’t get any redemption though – did they not deserve it?

You have to make the choice about how much time you’ve spent with a character. With Roz, there was a very definite decision that her denouement had to be distinct from all the others. She’s the first one of our characters to confess and she pleaded guilty in court, so her redemption is the fact that she puts her hand up and says ‘I have done wrong and I need to pay my debt’. Also, in the way that Tony Gates did in series one, she points a finger at the greater level of wrong-doing.

Some of the characters are doing things that are very unpleasant and none of our antagonists would ever do anything quite that unpleasant. I think probably the most unpleasant character was Chief Superintendent Fairbanks [George Costigan’s character, charged with child sexual abuse] from series three. I don’t think we could ever have an antagonist who did what he did because I don’t think there’s any grey area there, there certainly wouldn’t be for the audience. Having people who make bad decisions and who think that they’re good people… Roz thinks that she’s a good person. And in the end, good people admit their mistakes, but it takes her a long time to get to that point and as Steve said, he would have given up earlier.

All these characters – Gates, Denton, Waldron, Huntley, Dot, even Lakewell and Hilton, they’re all just people trying to extricate themselves from situations that bad decisions have landed them in. You don’t write characters in terms of true villainy.

No, and I’m not really particularly interested in that. There are a lot of genres that do that and ultimately they don’t appeal to me as a way of creating drama. In the real world of police corruption, it’s always much more mundane. Generally, it’s just about greed and there isn’t a grey area, they’re just greedy bastards who are breaking the law to get richer. Whereas our antagonists in Line Of Duty and the characters who are collateral to the antagonists, they are conflicted. They have to be conflicted so that the audience feels an investment in are they going to be redeemed or are they going to be punished?

You mention the collateral characters to your antagonists there, which makes me think of DC Jodie Taylor [played by Claudia Jessie]. It strikes me that one of the themes running throughout your writing is the damage that loyalty can cause, how it can blind people to wrong-doing. Ordinarily, loyalty is regarded as a virtue, but in Line Of Duty, it’s loyalty to the wrong people that causes all kinds of problems.

It’s more something which is a feature of the way institutions operate. Generally when people join an institution they’re signed up to the ideals and objectives of that institution, so people who are more powerful within that world often can convince impressionable people that their actions, whatever they are, are serving those ideals. You’ll always be quite surprised and sometimes quite anguished to find out how easy it is for people to cover up wrong doing by having that around them. The thing about the breast surgeon…

Gosh, yeah. I read that over the weekend.

You think, how could that happen? That’s the question you’re asking, yet I worked in hospitals for years and I know how that sort of stuff happens – people are frightened to question people’s ideals because they assume that people are in the institutions for the right reasons. It’s very easy to convince people that they’re doing the right thing.

Hastings has that same quality. Hastings has that quality of ‘we are after bent coppers, that’s what we’re doing’ and he keeps repeating it and everybody is following it and the audience is following it. Hilton will have had the same mantras, he will have led a retinue. And Roz does that quite overtly with Jodie, she appears to be a fantastic role-model for Jodie and a very supportive boss.

That line Jodie parrots about the police preserving life.

Exactly, yeah. Jodie parrots what Roz does because her assumption is that Roz, because of who she is and what her career history she is and what kind of person she is, has to be just and idealistic.

All that brings us back to the character of Roger Hurley in Bodies [a consultant obstetrician against whom the whistle is blown for a string of surgical errors, played by Patrick Baladi, who appeared as criminal solicitor Jimmy Lakewell in series four]. Was it always a goal of yours to work with Baladi again after that series?

Since doing Bodies, I’ve tried repeatedly to work with Max [Beesley] and Patrick and with Neve [McIntosh] and it just never really worked out. They’ve always been not available or the role hasn’t been right for whatever reason.

Actually, Patrick auditioned for Hilton [played by Paul Higgins] in series one but we thought he was too young. I’ve always been looking to work with him again and when this role came up, when the idea of Patrick popped into my head, it was just great that he was available and did a great audition and really suited the role and everybody was completely on board with it.

One of the joys of watching the scene where Huntley reads Lakewell his rights is that it’s always brilliant to watch people being brilliant at their jobs—it’s the joy of The West Wing, isn’t it, watching clever people being extraordinarily clever. You can’t make your characters too clever though, I suppose, as a writer a temptation would be to make them geniuses pulling off coups like that all the time.

I think you have to make them pretty clever. You have to make them either make the best possible decision in a situation or make a really bad one under obvious pressure. If you’re constructing a story based on people’s decisions, you as the narrator are allowed to step back and think ‘what’s the best lie this character can tell now to cover their tracks?’ We spend a lot of time thinking about that and saying ‘if the character comes up with this lie, what are the consequences, what are the questions that can be asked to challenge that lie?’ and working all that through. Sometimes, the character has the time to do that and other times they don’t. If you want to show them not making the absolute best available decisions then you have to dramatize all the pressures and distractions on them so that the audience will accept that if that decision leads them to greater complications than they’d anticipated, then they will accept that was the course of action that made the most dramatic sense.

One of the only frustrations of the series four finale was that we didn’t have any more from Jimmy Lakewell, he was caught and banged up in the course of ten minutes. Was there ever a plan for him to get away and not be jailed at the end?

I think that probably depended on how long that finale was going to be. The main story to address is the Roz story and when we were told we were moving to BBC One, I just thought, well, there’s no way we could have a ninety minute finale again because the only way we could do that with the BBC One News At Ten is if we went out on a Sunday night—and they’d never put us out on a Sunday night! [Laughs] Then they put us out on a Sunday night and it’s like well, it’s a bit late now! If we had ninety minutes I think we could have done more, but I was quite happy with what we managed to achieve within the sixty minutes.

Jimmy just ends up on that same wing of Blackthorn prison with [series three’s] Hari Baines and Manish Prasad, you can just imagine them in their own Orange Is The New Black.

A spin-off, please! Since you mention that, I have to ask if there’s any chance of an Endeavour-style prequel for Ted? Ted Hastings: the Ulster Years?

Er, that’s a definite no! [Laughs] I don’t think so, though I think Adrian would say ‘I can play a twenty-five year old’.

No, you’d start each episode with Adrian talking to camera in an armchair by a roaring fire saying “Did I ever tell you about the time I…” and it fades to flashback.

[Mercurio makes polite, non-committal noises]

Moving on! This may be a stupid question because if they hadn’t done so, you wouldn’t have a plot, but the fact that experienced officers Tim and Roz, neither of them trusted the law to protect them, despite the situations in which they found themselves being accidental. Did you intend that to be a critique?

Yeah, I did and I did the research! It’s really, really hard to get off with self-defence, really hard. Maybe as police officers they would have had a better time of it, but generally if you found yourself in that situation you would be better advised to plead guilty to manslaughter for the minimum three years. If you take the risk of fighting a murder plea with self-defence and you fail, then you will be convicted of murder and that is a mandatory life sentence. As a police officer, you’d know that. If you’re sitting in that room with a dead body next to you that you are responsible for, you’re thinking the next thing I do now could end up with me being convicted of murder on a majority verdict and spending the rest of my life in prison.

Hence series four.

Hence don’t take that chance! I’m not saying everybody wouldn’t take that chance, I’m saying in that particular moment, the character is aware of the fact that you have to prove so much. You have to prove that you warned the person, that you were in a position to defend yourself in a way that could do them serious injury, you have to prove that you gave them a way out… You have to prove all these things and with no witnesses, it gets pretty hard.

You might argue that on the balance of what we know about juries, a lone woman in a vulnerable situation, maybe she’d get away with it, but then Roz went to his house, he’d blown the whistle on her, she took steps to cover her movements… She knows all that. And that’s not going to play well in front of a jury. That’s going to put doubt in the jury’s mind. Some of that was originally in Roz’s final confession but it kind of got bogged down with it becoming such a long explanation when she was being emotional that we ended up trimming bits out.

I think if people really are interested in these things, they’ll often go and look them up. I don’t have a huge amount of respect for the people who just go immediately on Twitter, with no knowledge of the criminal justice system, and decide that they know enough to be able to give an opinion. Then there is a group of the audience who are curious and will enter into a constructive debate. Someone who does know about the criminal justice system will be able to tell them that the defence of self-defence is a very precarious one.

Jed Mercurio, thank you very much!

LINE OF DUTY SERIES 4 AND COMPLETE SERIES 1 – 4 BOX SET ARE AVAILABLE ON DVD FROM 8 MAY