MONICA Dolan has two films at this year’s Glasgow Film Festival. That’s showing off, I tell her. “At London I had three,” she points out amiably.

Perhaps it shouldn’t be a surprise. Dolan is British drama’s not-so-secret weapon. Born in Middlesbrough in 1969 and brought up in Surrey, the daughter of Irish parents, she has been a regular on our screens since the 1990s, most notably in the BBC sitcom W1A, as George MacKay’s homophobic mum in the film Pride, playing Marion Thorpe opposite Hugh Grant in A Very English Scandal, Russell T Davies’s take on 1979s liberal leader Jeremy Thorpe’s downfall and winning a Bafta for playing Rosemary West in Appropriate Adult in which she offered a chilling study in stillness and anger. I’m still having nightmares about those glasses.

She’s also turned up in everything from Vanity Fair to The Bill and Wolf Hall to Death in Paradise. And that’s before we get to her roles on stage. “God, she works hard,” Russell T Davies once said.

Not today though. It’s Friday, Valentine’s Day, and she’s at home in London, surrounded by tulips. She bought them herself, she says. “If you think, ‘Oh I need a bit of cheering up …’ They’re my favourite flowers.”

Over the next hour she will chat about everything from her new films Rialto and Days of the Bagnold Summer, directed by Simon Bird of The Inbetweeners fame and co-starring Earl Cave (the son of Nick Cave and Susie Bick), to her Irish parents, growing up in the suburbs, playing the Edinburgh Fringe and why actors love getting a part in Death of Paradise.

LET’S START WITH DAYS OF THE BAGNOLD SUMMER. WHAT WAS THE APPEAL OF DOING A FILM BASED ON A GRAPHIC NOVEL?

It’s a coming of age story about a mother and son. It’s very much a coming of age for both of them. Part of her has been trapped as a teenager really and spending this summer with her teenage son takes her back to those times.

That was part of the graphic novel I thought that was really present, her sort of melancholy. It’s humorous as well.

It’s very much a hymn to the suburbs and I was brought up in the suburbs. Simon the director was brought up not far from me. When I went to meet him, we both kind of knew what we were talking about.

YOUR CO-STAR WAS EARL CAVE. WHAT WAS HE LIKE TO WORK WITH?

He was brilliant right from the audition. He’s such a lovely person and he’s got a lovely mum and he obviously treats her well.

I remember saying to him, ‘you’re doing your job properly if you’re being mean to me in this bit. Don’t hold back from being spiteful and unkind. If you try and be too nice the scene’s not going to work so don’t be afraid to be horrible.’

So, he certainly did.

But he was really smashing from the word go. We used to get the car in together every day. That helped.

DID YOU ASK HIM QUESTIONS ABOUT HIS DAD?

No, I didn’t ask him a single question about his dad. In fact, I bumped into him recently with his dad and that’s the first time we’d met.

WAS THERE A LOT OF HEAVY METAL BEING PLAYED ON SET?

There was loads of heavy metal getting played in the car on the way because he was trying to get into that. It was quite fun because all the way through the film my character Sue is saying, ‘Oh, why are you playing that?’

In the graphic novel she’s into James Taylor and things like that, so I was trying to give him CDs of James Taylor to play in the car. But he wasn’t having any of it. I think one day in the car I got to play some Barry Manilow, but that was short-lived.

YOU’RE TELLING ME THAT THERE AREN’T A LOT OF BLACK SABBATH RECORDS IN YOUR VINYL COLLECTION, MONICA?

I’m saying there aren’t a lot of Black Sabbath albums in Sue’s record collection.

YOUR OTHER FILM AT GFF IS RIALTO, SET IN DUBLIN. WAS IT A CHANCE TO CONNECT WITH YOUR IRISH ROOTS?

Since the last time I was in Ireland my father passed away and I spent some time with his brother and that was really interesting, talking about them both coming to England to look for work and just looking at what my father’s life was back then. And because I’m an adult now I could see more clearly than when I was younger what his responsibilities were.

Not the day after Brexit, but the day after that, I got my Irish passport. I’m really thankful for my parents for that. But I also think that did something for my identity actually. That made it OK to be British and Irish.

[Growing up] my parents were very adamant that I was going to have a British passport. Part of that might have been the money. They didn’t want to pay for two passports. They were very concerned that I’d be British, I think, and have the opportunities that were there at the time, I suppose.

Ireland is so European now. That’s what I really noticed when I went back, so I’m just lucky and proud to be both.

WHEN DID YOU KNOW ACTING WAS THE THING YOU WANTED TO DO?

At senior school I played the Artful Dodger in Oliver. I just never had a reaction like that to anything I had ever done. I got some focus from it. I thought, ‘I’ll have some more of this.’ I joined a youth theatre. I suppose when you’re young it doesn’t feel like you’re being creative because you’re used to playing.

And then I met lots of people who were going to drama school and I thought, ‘Oh, that’s a possibility. If you see the choices, you can have them.

I did all sorts of things. I worked as a waitress and a bar person. I worked at the job centre in Worthing. I was a temp for a couple of years while I was trying to get into drama school.

YOU CUT YOUR TEETH ON ALL THE USUAL SHOWS, INCLUDING THE BILL.

Everyone worked on The Bill. I remember going for an audition with an obscure Russian director who was doing Measure for Measure, I think. Eventually he said something to his interpreter and his interpreters said, ‘He wants to know what The Bill is because all of the actors who come in have got The Bill on their CV.’

For the generation before me it would have been Juliette Bravo or something. They’re good things to cut your teeth on and meet lots of people.

I SECRETLY BELIEVE DEATH IN PARADISE IS THE DREAM JOB FOR AN ACTOR. TWO WEEKS IN THE WEST INDIES, WHAT’S NOT TO LIKE?

I think we all liked doing that one. It’s fantastic for guests because you’re there for 10 days. The girl who was murdered, she was just there for a little bit and then a few flashbacks, so I think she got loads of time off.

YOU’VE PLAYED A NUMBER OF REAL PEOPLE, FROM JEREMY THORPE’S WIFE, MARION, TO SERIAL KILLER ROSEMARY WEST. WHAT SENSE OF RESPONSIBILITY IS INVOLVED IN THAT?

It’s a difficult one. It has to be a very considered choice whether you meet the person or not. I remember an actress saying, ‘If I spend too much time with them, I end up feeling too much responsibility to them.’

There is a responsibility to that person, but there’s also a responsibility to the script. A very useful tool is to stay objective so you can make decisions and so you can talk to other actors about the character as well.

In terms of how I approached both Marion Thorpe and Rosemary West, it was through reading and through footage, maybe in quite a clinical way.

I had a small part in a Mike Leigh film [Topsy-Turvy] and one of the things I learnt from that was always to call the character ‘she’. And apart from protecting you, it’s really helpful. You don’t get yourself mixed up with the character. You don’t go, ‘I wouldn’t do that.’

Because most of your day isn’t being them. There’s a lot of downtime and you need to be able to be a good co-worker. Empathy for a character is important but seeing things too much from their perspective maybe isn’t as helpful as you imagine it might be.

YOU’VE TALKED IN THE PAST ABOUT HOW ACTING IS A BIT LIKE BEING A DETECTIVE OR A PSYCHOLOGIST.

Did I say that? It is in that you’ve got your script and you’re always looking for clues. I tend to look up things a lot when I’m reading a script.

When I was doing Pride our character’s house was in Bromley and I remember that George MacKay’s character, my son, was on the way back from London.

A friend he had been staying with was also stopping at a station in Kent. And I remember it being useful looking at the train line because then I knew if there was part of the journey my son would be travelling on his own, so I knew how worried to be about him.

Things like that sound silly but if it’s your character’s main priority.

YOU WROTE AND PERFORMED A SHOW B*EASTS AT THE FRINGE IN EDINBURGH IN 2017. WHAT WAS THAT EXPERIENCE LIKE?

It was incredible. At the Edinburgh Festival you don’t get a day off unless you ask for one. So, doing a show 11 days on the trot and then 14 days on the trot was something I was concerned with before I went, whether I would have the stamina.

In Edinburgh if you’re not careful you can get trapped in the ‘how am I doing?’ syndrome. I was incredibly lucky with my dressing room. I was sharing it with these eight blokes. It was fun. Everyone has their moments. Someone’s crying because they got two stars and then everyone’s excited because someone’s won a Fringe First. I made some lasting friends there.

I remember I fell asleep in the corner of the dressing room and when I opened my eyes one of them had put a coat over me and another one had put a Kit Kat next to my head.

IF SOMEONE WAS PLAYING MONICA DOLAN WHAT WOULD BE THE KEY REALISATION THAT WOULD UNLOCK EVERYTHING ELSE FOR THEM?

If I knew that I would know the meaning of my own life and I’d be very rich, and I’d be very happy already.

Days of the Bagnold Summer is on at the GFT on Wednesday, March 4 at 6pm and Thursday, March 5 at 3.45pm. Rialto is screening at the GFT on Thursday at 8.30pm and Friday at 3.45pm.