Line of Duty's Adrian Dunbar: "Hastings has been a game-changer for me as an actor"

For viewers, though, the rules of the game have changed unnervingly. Ahead of Sunday’s series four finale, the previously unimpeachable Hastings stands accused of sexist appointments, unfair treatment of a junior, membership of a “masonic organisation”, and even potentially being the senior figure, so far only identified by the letter H, who ran the network of corrupt police officers that has been a sub-plot throughout Jed Mercurio’s masterly police drama.

Admirers of the character can take some comfort from the fact that the internal phone directory of the fictional police force has a packed H section (including Huntley, Hilton and Hargreaves), which gives Supt Hastings some crowd cover. Even so, the leader of AC-12 has been painted in darker shades this time, which Dunbar has enjoyed.

“The great thing about Jed’s writing is that everyone is complex and awed, and there are always more complications. There’s a line in the last scene of this series, where you think, ‘Where’s that come from and where’s it going to go?’”

Dunbar is no stranger to crime dramas, having played a part in everything from Crackerto Inspector Morse to Death in Paradise. “There are so many police series that we all end up playing a cop of one hue or another eventually.” His own personal favourite is Inspector Montalbano, the dashing Italian detective. “I think it’s the most radical cop show on telly. I do like the dark, gritty psychological thrillers, but sometimes we need a little respite from that.”

Dunbar grew up in Enniskillen in Northern Ireland as one of seven children in a Catholic family and his own early experience of the policewas framed by the Troubles. “The RUC [since 2001, the Police Service of Northern Ireland] were a sectarian organisation, given that they were drawn from one section of the community. It wasn’t my section of the community, so it was hard not to see them as an oppressive force.”

But his views of fictional police were formed elsewhere. “I grew up seeing Z Cars and I was hugely excited by Jimmy Ellis [the Irish actor who played policeman Bert Lynch and who died in 2014]. His wife, Robina, says she sees a lot of Jimmy Ellis in Ted Hastings, which is a very high tribute; that’s a bit of a touchstone.”

He sees Hastings as a mix of Ellis, plus actors Gordon Fulton and Fulton Mackay, and football managers Bill Shankly and Sir Alex Ferguson. “Leaders of men, highly moral, very straight- talking and terribly loyal to their people.”

As a teenager, he thought he was going to be a musician, and performed with an Elvis Presley impersonator for a couple of years. But he left Northern Ireland to study acting at the Guildhall School of Music and Drama, fell in love with London and decided to stay.

“It wasn’t a good time,” says Dunbar, referring to the era when there were frequent IRA bomb threats and a “ring of steel” round the city. “But London historically has been worried about the Celts ever since Bonnie Prince Charlie got as far as York.” He loves working in a now peaceful Belfast. “The mood of the city has changed, people are allowed to be themselves again and not find themselves as pariahs.”

One of the changes in dramas featuring the police is that characters are often now given a hinterland, although Ted Hastings might have trouble competing with Dunbar’s many passions, which stretch from Samuel Beckett and Oscar Wilde – both Enniskillen boys – and the art of Bridget Riley and Howard Hodgkin to Arsenal, his country-jazz band, Adie Dunbar and the Jonahs, and the new wave of Irish writers.

Hastings, whom Dunbar describes as “like all of us, struggling to be good”, is the longest- running character he has played. “The downside is you look at photos of yourself when you started the series and I nd as you get older, you get older quicker – ah, the vicissitudes of time.”

Line of Duty concludes on BBC1 on Sunday 30th April at 9:00pm