Vicky McClure: 'You won't be able to get up and make a cup of tea, there is an awful lot going on in Line of Duty this year'
Hugely popular police drama Line of Duty, which is shot in Belfast, returns for its fourth series this weekend, and it promises to be the best yet. Kate Whiting reports
The wait is almost over for the five million-plus fans of Line Of Duty - and series four is set to be the best yet, promises actress Vicky McClure.
"I think it's the most complex case we've ever dealt with," says McClure, who plays DS Kate Fleming in the Belfast-shot police drama. "The forensic side of it is going to give the audience a lot to play with.
"You won't be able to get up and make a cup of tea, you are going to have to listen and pay attention to lots of small details. There's an awful lot going on this year."
Last year, Line Of Duty was crowned BBC Two's most successful series in 15 years, averaging 5.1 million viewers each week. It's now transferring to BBC One and, with new guest stars and a few major storylines tied up, it's the perfect time to start watching.
A new twist on the standard police procedural drama, Line Of Duty follows anti-corruption unit AC-12, run by Kate, who was promoted at the end of season three, and colleagues Superintendent Ted Hastings (Adrian Dunbar) and DS Steve Arnott (Martin Compston).
In the explosive series finale, AC-12's DI Matthew 'Dot' Cottan (Craig Parkinson) was finally exposed as 'The Caddy', the corrupt officer who'd been covering up historic child sex abuse.
The Caddy had already killed Keeley Hawes's character, DI Lindsay Denton, who'd been the target of an AC-12 investigation, and then tried to frame DS Arnott.
"Towards the end of the writing process, it was still in play that The Caddy would elude detection and point the finger at someone else," writer Jed Mercurio explains of the decision to tie up the storyline that had stretched throughout the first three series.
"At the end of writing episode five, there was a possibility that The Caddy would have Steve killed and Lindsay would be blamed for it, but it landed Lindsay back where she was in series two, which was going to prison again. It felt too circular."
Mercurio is excited to be starting "a new chapter" and states: "I'm so grateful to the fans, to be in a position where an audience discusses your series and speculates on what might happen next, that's really why you do this job."
In the first episode, we're introduced to the main "antagonist", DCI Roz Huntley, brought to life by series newcomer Thandie Newton, who follows in the footsteps of Lennie James, Hawes and Daniel Mays as the focus of an AC-12 investigation.
Having been off work to bring up her children, she's under huge pressure to climb back up the career ladder and crack a case called Operation Trapdoor, while coming up against forensic co-ordinator Tim Ifield (played by fellow newbie Jason Watkins).
"One of the higher aims of this series is to look at that theme of what is truth? What is objective reality? If you weren't in the room, and you didn't witness what happened, how can you derive an understanding of what actually happened between those two people?" says Mercurio, who acknowledges his theme uncannily echoes the era of "fake news" and "post-truth".
"Over the years, I've been getting more and more exasperated at the lack of respect for facts and proper research, being able to tell the difference between an opinion and a fact. Unfortunately for the world, that has become a bigger issue now than it was."
The series is shot in Belfast and Mercurio starts the conversation over plot lines with long-standing cast members Dunbar, McClure and Compston long before they get there.
As DS Fleming, Vicky McClure has to go undercover and her all-action turn in series three saw her tipped to play the next James Bond. But the truth is a little different for the actress: "Last year, I'm under the bridge and say, 'I'm too knackered to run'. Jed knew I would be knackered, and I delivered that with conviction every time."
Compston says there'll be some friction between Arnott and Fleming due to her promotion.
"Steve sort of owes everything to Kate, because she believed in him and wanted to get him out. Now they're at a parity career-wise because they're the same rank, but he's also going for a promotion. He is a little smart-ass, he thinks he knows better than everybody, so it's a lot of fun to play."
"Yeah, he is unsettled that she's now the same rank as him," agrees McClure. "We have quite a bit of fun playing around with that. It's important for Kate and Steve to have that realistic relationship, they've got each other's backs, but they've also got to fulfil their own ambitions."
McClure is thrilled to have Thandie Newton and Jason Watkins on board. "I love the fact that the casting is never obvious," she says. "Thandie's character is so far removed from her and any character we've seen her play. And the same with Jason, his character is quite unique, we can't quite work him out. What great additions to the Line Of Duty family."
Newton, who describes McClure as "spellbinding", says: "I had a call from my agent, who's represented me since I was 17, and she said, 'If you ever want to work on British television, this is the best thing you could ever do'."
As DCI Roz Huntley, Newton squares up to forensic co-ordinator Tim Ifield (Watkins), who's responsible for examining the whole series of crimes and murders that are suspected of being grouped together. Newton calls Ifield "a fly in the ointment".
"As a senior investigating officer, the facts are there, but then it's knitting those facts together. It's real Sherlock Holmes territory."
- Line Of Duty, BBC One, Sunday, 9pm