Line of Duty’s Martin Compston on DS Steve Arnott: I put on the waistcoat and feel him creeping into me

The Line of Duty actor says he has to keep up his English accent for the whole shoot – except when talking to his mum or his new wife...


For Scottish actor Martin Compston, Line Of Duty is an even tougher gig than you may have initially imagined. Not only does he have a lead role in Jed Mercurio’s tense, febrile and often action-packed drama – he forces himself to speak with an English accent for the four-month shoot, even during his down-time.


Back in his hotel, or talking to friends, the “very VERY proud Scot” keeps up Arnott’s yap yap English accent for the whole run. There are only two exceptions – when he is speaking to his mum or his new wife, American actress Tianna Chanel Flynn with whom he tied the knot in June last year.

“Other than speaking to my mum, I will keep speaking English,” he tells “Because she’s my mum, you have got to speak to your mum in your own voice. And my missus too, though for series one she wasn’t there. If she comes to visit I speak English if I’m around crew and I will speak normally at night.”

The reason he makes all this effort is to help him cope with the drama’s “challenging dialogue”: “We have got these massive scenes and accents can be like being at the gym – the harder you work, the stronger you get with it.

“With some actors, they are absolutely brilliant at impressions, they can tell you a limerick or a joke in any accent whatsoever but they think from that they don’t need to do the work and they can’t sustain it over a period of time. And for the crew as well, it can be quite jarring for them. If you keep switching from Scottish to English people sort of listen for mistakes, whereas if you stick with the accent people just sort of accept it. There will be times where I know I have f****d it up but people won’t be listening for it.”

Accent notwithstanding, Compston seems oddly fond of Arnott, the AC-12 detective he has played for three series and who opens series four stewing over the fact that he and DS Kate Fleming (Vicky McClure) now share the same job title (she was promoted at the end of series three). Still, once again they settle on a new case with the tenacity we have come to expect from the detective pairing.

“When I put on the accent and put on the waistcoat, I can sort of feel Steve creeping into me. It’s a joy in that way.

“He’s an arrogant little prick. I intentionally make him like that because you want to make these characters interesting – he’s the hero but he’s not instantly likable. He’s a smart-arse and he thinks he knows best and that his way of solving the case is always the best which has got him into trouble a couple of times.

“There are things [Superintendent Ted] Hastings [played by Adrian Dunbar] respects in him – he is tenacious and he will see things through to the bitter end and sometimes that’s to his detriment. It’s really a satisfying thing to have such ownership.”


In the last series Arnott was emotionally involved in a case focusing on child abuse at a care home which – it turned out – involved the antagonist Danny Waldron (Daniel Mays).

“Arnott gets very attached to the cases he’s on and sometimes too attached. The sex abuse storyline obviously related to real-life cases and to Savile and kudos to the BBC for allowing us to do that. It was something I was angry abut in real life and found very easy to connect to.”

This series sees Thandie Newton play the subject of AC-12’s investigation – wily officer Roz Huntley – but Arnott will have “a big story arc” and “be in situations that he hasn’t been in before,” adds Compston who, like all the cast, is tight-lipped on any potential spoilers.

Having filmed the current series, he thinks the drama’s previous run – which saw the end, finally, of Craig Parkinson’s corrupt cop The Caddy – is his favourite.

“That would be hard to top,” he says, but adds that the new run is “a slow burn… it’s definitely a new beginning.”

He’s not clear how long the show will continue, with a fifth series already commissioned and a sixth up in the air. Compston has a sneaking feeling that Mercurio – or the BBC – could decide to end it after that.

“When I first met Jed his idea was to do five but I don’t’ think he quite anticipated the success either. And we take these long breaks in between so there’s no fatigue on us. So as long as Jed is willing to write it, I’d love to do more. It’s definitely got another one, probably two [series]. Five could be the last one but I don‘t know who would be there in terms of cast. My assumption is that it would be five to six [more].

“I’d love to do as many as they want. He’s sort of mine. He’s Jed’s on the page but when I get a script I know exactly how he will react.  You instinctively know what Steve will do and I like that.”


Line of Duty series 4 starts on BBC1 on Sunday March 26 at 9pm