Line of Duty's Adrian Dunbar: "I’d love to do a sitcom with Anna Maxwell Martin"

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Noooooh, please, for the love of God, don’t have upright, uptight, old-fashioned Hastings going on a dating app! “You never know,” the actor says, in his wry, understated way, “Jed [Mercurio, series creator] might decide to have a bit of fun with him.”

This is the first time in my life that such an antique, deity-summoning phrase has come out of my mouth, but then the LoD effect is sweeping the nation. We are all talking in acronyms now – blithely referring to AC-12, the OCG (organised crime group) and SCG (serious crime group); DNA, DIs and DS-es tripping off our tongues with ease. And, above all, H. Please Jesus, Mary and Joseph do not say our guy, our beloved Hastings, is the most bent of bent coppers.

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Dunbar is, of course, not saying a word. He and fellow regulars Vicky McClure (DI Kate Fleming) and Martin Compston (DS Steve Arnott) are well-practised – five seasons in – at the Seamus Heaney line, “Whatever you say, say nothing.” But they also like to tease…

We’re discussing a long scene that features in the finale, with Hastings (last seen banged up in a prison cell, shouting “I am not bent!”) the subject of a lengthy interrogation, when Dunbar adds: “I don’t know how you’re going to put that in your article?” I’ll just say that there’s going to be a long scene of interrogation. “There could be…” Ha, here we go. “You always have to do that with Line of Duty. ‘There’s a possibility of...’”

I wonder whether he is as discreet in his private life? “Yeah, I can keep my counsel. Absolutely. A friend needs to be able to confide in you and to be confident they can do that. Those things are important; they’re the bedrock of most friendships.”

Mercurio originally intended Hastings to be a shambolic genius, in the Columbo mould, whom everyone underestimates, but in the audition process, this changed. “That’s a very attractive type of character, absolutely, but we all came to the decision that it would be useful if the character was from outside the police system, making him a Catholic in the RUC [Royal Ulster Constabulary] – so he was an outsider within an organisation.”

This also meant Dunbar could keep his own accent. “I come from that generation where we really love the likes of Bill Paterson and Pete Postlethwaite and Alun Armstrong – all working-class guys who kept their accent. So I think where you can keep your accent you should, for greater authenticity,” he says. “But I did The Hollow Crown [as Plantagenet], for instance, and that was definitely not my own accent!”

Martin Compston, by contrast, speaks pure Estuary for the duration of Line of Duty filming, including when he’s not on set, when in real life he actually has a broad Greenock accent. “Yeah, he keeps his accent going and then now and again we might have a party and at about one o’clock in the morning, he just goes into Scots.” That must be a bit weird. “It is weird because we can’t understand a word he’s saying by then!”

We all have our favourite Hastings-isms. Mine is, “I am calm! I am bloody calm!” Although it’s a close-run thing with “Now we’re sucking diesel”, with “I didn’t float up the Lagan on a bubble” close behind. He was fortunate, he says, that Mercurio was receptive to his suggestions as to how Hastings could be. “People start to get involved with the character,” he explains, “and you start adding little bits of characterisation, with both myself and Jed putting in these little Northern Irish-isms and people get interested in that."

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But do you actually use those expressions yourself? “Not necessarily, no,” he says. “Those were phrases, I have to say, that my father used.” Dunbar decided that Hastings would be a good man manager – “not necessarily a good woman manager [cue “She’s a great wee girl doing a bang-up job”]. When everyone is in uniform, he treats them all the same – as though they are all men.” He gives a big laugh. “He is a bit old school. I think people understand that about him. He’s a bit Bill Shankly and Alex Ferguson.”

Is he surprised that Hastings has become a heartthrob figure? “Yeah, well, that’s a subject of some amusement, obviously,” he says, as dry as can be. That wasn’t intended in the script? “No, we didn’t expect for any of that to happen.” You must have a laugh about it? “We do, we do – I mean obviously there’s the Gill Biggeloe thing and all that to-do,” he says, referring to AC-12’s legal counsel, played by Polly Walker, who managed to get Ted into bed.

He was even asked onto Woman’s Hour to explain Hastings’s homme fatal appeal. “They were asking me why I thought women responded so much to Ted and I think it’s because they all realise they could have him round their fingers within 20 minutes. Women like that. ‘Oh, Ted, he’s so easily led.’ In personal relationships I think that ’s where he’s at.”

Hang on, Ted did resist Gill’s charms for a time. “He did, yes – he was trying to hang on to his marriage for as long as he could."

Dunbar is the eldest of seven children – he has two brothers and four sisters, none of whom has followed him into the arts – and was born in a working-class area of Enniskillen in 1958. His father was a joiner and the actor has spoken about his regret that they were never able to talk in a meaningful way. The family moved to Portadown, which he has described as “the most marginalised of all the Nationalist communities in the North… if you were Catholic, you literally couldn’t walk up the street without getting into some kind of conflict… Everyone on our estate was living in fear.”

He himself was dragged out of a shop because of his school uniform and beaten “while the RUC strolled by”. Elsewhere, Dunbar has talked about seeing the RUC as a “sectarian” and “oppressive force” when he was growing up. The family moved back to Enniskillen when the Troubles became too intense.

As children, he and his siblings watched the Ealing comedies on television and there was a piano in the house and always music. “My mother was a wonderful singer and we listened to lots of tenors , Mario Lanza and Josef Locke [Dunbar co-wrote and starred in the 1991 film Hear My Song about the great Irish tenor] but also Kathleen Ferrier and D’Oyly Carte and Gilbert and Sullivan. All of it was accessible and fun.”

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While working in an abattoir in his teens, he played bass guitar and sang back-up vocals with an Elvis impersonator. “It was a very good job at the time, I really enjoyed it.” He later became lead singer in his own band – Adie Dunbar and the Jonahs, playing a style of music he describes as “folk jazz”. They released an album called Two Brothers with some songs written by him, including Turn Me Around, about a forlorn, boozy tumbleweed of a man. He has a beautiful voice. The night of our interview, he is performing jazz standards in a Pizza Express in central London.

He started acting and was encouraged to apply to the Guildhall School of Music and Drama in London. He was awarded a place, graduating in 1983, and fell in love with the city where he still lives with his Sydney-born wife, Anna Nygh (they have been married for 33 years), describing his Crouch End neighbourhood in north London as a “fantastic part of the world”.

Their daughter, Madeleine, 32, works in New York and in the UK, writing rap songs with kids who are struggling and getting them back into school. His stepson, Teddy, from Nygh’s first marriage, runs his own film company, Fully Focused, working around issues such as knife crime and homelessness among the young.

He has appeared in terrific films like My Left Foot and The Crying Game, and in the television series Inspector Morse and Cracker. He has played Oscar Wilde and Brendan Behan on stage, often performing at the Abbey Theatre in Dublin and the Lyric in Belfast. He writes, directs, acts, sings – what more could a creative man want?

Well, he wouldn’t say no to a London play. “I end up working in Ireland the whole time,” he says, “which I love and I can go home and see everybody, but it would be nice to be like other people who live in London and just head down town every day and feel like a proper actor working in the West End.”

When I ask him who he would like to work with now, he checks that the Line of Duty audience will have been introduced to the new star character – his chief interrogator, played by Anna Maxwell Martin, who has made it her mission to bring Ted down: “She’s very funny and I’d love to do a sitcom with her.”

He reveres Jimmy McGovern and Paul Greengrass as writers and also Lisa McGee, the writer and creator of Derry Girls. “What’s interesting about her writing is that she manages to shed light on a period that was very, very difficult without explicitly referring to it.”

Dunbar goes on to talk about the two education systems in Northern Ireland: one is state-run and largely Protestant; the other is run by the Catholic Church (he was educated by the Christian Brothers). “I don’t think the people in the rest of the UK really understand this. You might be in a kindergarten with your best friend who lives next door, then at the age of five you’re made aware that that person is different, and they head off in one direction and you head off in another. And that is basically where the dysfunction within Northern Ireland starts. In the 1960s in America, they had bussing – and in Northern Ireland, they still have bussing. They are bussing children from one side of the city to the other.” He is passionate about introducing integrated education, and has said: “You can’t make someone fear another person if they shared a desk for seven years.”

As for the recent tragic murder of journalist Lyra McKee amid rioting and fires, he is not at all surprised. “This is the result of Brexit. Brexit has destabilised Northern Ireland terribly. And we can’t go back to a hard border. If we did I’m afraid there will be civil disobedience, which could lead anywhere, really. It doesn’t bear thinking about. It certainly didn’t bear thinking about when everybody was campaigning to leave the EU. No one gave a thought to Northern Ireland and what might happen.”

With our time coming to an end, we discuss Mercurio’s ruthless dispatching of even the biggest stars on his shows, making him the serial killer of screenwriting – the latest victim being Stephen Graham’s undercover officer John Corbett.

We know there will be a sixth series. The big question is, will Hastings be in it? “If you think about it, Jed has put the sword through so many brilliant actors. You just think, ‘None of us are safe. It could happen at any time.'”

I accuse him of being disingenuous when he affects vagueness about the ending of this season. Come on, Adrian, of course you know what’s going to happen! “Well, yes, I do know what happens in the last episode. I don’t know, however, what the edit of it is like, and the edits do throw up different things. Bits you thought were going to be in sometimes aren’t.”

In this context, I bring up The Big Chill – it turns out Dunbar was unaware that Kevin Costner was supposed to be in the 1983 film in flashback but ended up just being a corpse in a coffin. That was certainly an edit that Costner wasn’t expecting! “They probably made a wise decision there,” he says cheekily

He is really grateful for this plum of a role. “Obviously, it’s brilliant for an actor at my stage in my career to get a part like this. I’ve been banging away at the coalface, if you like, for many years now, and I’ve done some really wonderfully interesting work, I’ve been very lucky. But I’ve never had a character that I could really throw my stuff at.”

I persist and put it another way. Is there an element of the LoD actors putting their careers on hold waiting for Mercurio to reel them back in for the next season? Isn’t it conceivable Dunbar might get a more attractive offer – let’s say, that longed-for role on a West End stage?

“Oh, I see,” he says. “Well, I’m sure Jed would find a way to say, ‘Poor old Hastings, that was terrible that car crash, wasn’t it?’ But I’m not going to get anything better than Ted. That’s not going to happen, so don’t worr y. And I’d miss everybody too much.”

Line of Duty airs on Sundays at 9pm on BBC1