The Version Interview... Martin Compston on Line of Duty Series 4

When DCI Roz Huntley (Thandie Newton) captures a serial killer, Forensic Coordinator Tim Ifield (Jason Watkins) alerts AC-12 to a possible miscarriage of justice.

Series four of the hit drama, written and created by Jed Mercurio, begins with DCI Roz Huntley and her team in the thick of a career-defining case, Operation Trapdoor.

Under intense pressure to catch the culprit and prove herself to her superiors, and facing conflict with her colleague, Forensic Coordinator Tim Ifield, it’s not long before AC-12 decide to probe her handling of the investigation. A mother of two and wife to husband Nick (Lee Ingleby), Roz will do anything to stop her life unravelling. Anything.

Martin Compston tells us more...

Where do we pick up with Arnott and AC-12 this series?

A bit of time has passed since the end of series three, we’re all back at the office, and Steve’s back in his waistcoat being his arrogant little self again. He’s really pushing for a promotion and things are just a wee bit frosty between him and Kate. They always have that love/hate relationship, when they really need each other they are there for each other but they really can annoy each other at times. They were probably my favourite scenes, when Vicky and I are getting on each other’s nerves.

We seem to see a different side to Arnott each series, is this the case in series four?

I love playing him, I genuinely do. It’s a really tough part at times because he’s the moral compass of the story and a lot of the information comes through him. As ever with Line Of Duty, there are some big shocks to come and people are in for a few surprises.

You’ve played him for four series now, does it take a while to get into character or do you feel like him again as soon as you’re back on set?

The accent is a big help for me so a couple of weeks beforehand I start practising the voice. When I put that voice on and then when I put the costume on I do feel myself slipping into AC-12 mode.

Do you stay in the accent throughout filming?

I try – I still speak Scottish to my wife and my Mum (they probably wouldn’t speak to me otherwise) but I try as much as possible to stay in character just because the language is so challenging. They’re amazing scripts but they’re so in depth, complex and full of police jargon that you really need to keep on top of the voice work. I’m not as militant as years gone by.

Does the fact you’re so close to Adrian and Vicky help with the AC-12 scenes, especially the interrogation ones?

We owe a lot to Lennie James; Lennie set the standard for it. The first one we ever did was me, Adrian and Lennie and Lennie insisted we did it straight through.

Adrian, Vicky and I go to each other’s flats to run lines as we all live in the same building when we’re filming. They’ll do a bit more cooking than I will but I actually cooked for them for the first time this year!

Tell us about DCI Roz Huntley…

All of Jed’s characters are so well formed and developed and Thandie is a fantastic actress who comes with bags of experience. She was an absolute joy to work with.

What was it like working with Thandie Newton and Jason Watkins?

Because the show has built up a great reputation and the scripts are so good, people like Thandie and Jason were genuinely excited to be involved. They were big fans of the show and I’m a big fan of both of them so it’s gratifying. They wanted to do well on it; it wasn’t just another job for them. We’ve been incredibly lucky over the years with our guest stars and this year is no different.

Forensics is at the heart of this series, was that interesting to learn about?

Yes and no. It could be very tricky to learn. There’s a word exsanguination that will stay with me till the day I die. It was really interesting but you need to make it look like you know what you’re talking about. It’s not easy but we don’t make excuses for the audiences and I think that’s why people love it, they really have to listen in.

Line Of Duty has moved from BBC Two to BBC One due to its success, why do you think the show is so popular?

It’s got fantastic scripts, a really solid cast and always great guest stars coming in. I’m guilty as anybody of binge watching Netflix with a hangover and we live in a culture where everything is so immediate, but Line Of Duty has that old fashioned way of ending each episode on a cliff hanger and leaving people all week talking about it. People really get in to it and they don’t want spoilers.

What can viewers expect from the new series?

In classic Jed Mercurio fashion everything’s not as it seems, there are a couple of big shocks and twists and just more Line of Duty madness!