Charlene McKenna can talk. Nobody is likely to confuse the Monaghan-born actor with one of those Californian hipsters who regard any conversational engagement as a betrayal of their carefully maintained cool. Her accent entirely unaltered by several years living in the funkiest corner of east London, Charlene comes across as if she’s till working behind the bar of the family’s pub in Glaslough. The word “unaffected” hardly covers it.

She's done well for herself. This week, she appears in Kieran J Walsh's feisty drama Jump . Adapted from a play by Lisa McGee, the picture follows four young people as they career about Derry on New Year's Eve. She has a regular part in the Victorian TV romp Ripper Street . She also had major roles in Raw and Pure Mule on RTÉ. Hang on. Weren't all those shows shot in Ireland?

“I am in London for or five years now,” she muses. “It’s grand. But oddly I keep getting to film things back here. Maybe I am destined to be here. Ha ha!”

So how did she make the journey from the Border counties to a place on the hot list? One doesn’t imagine that casting agents make too many journeys to her corner of the country.

“I am the first one in the family,” she says. “I don’t know where it all came from. I have often tried to find the links. There was always music in our house. Maybe that was it? Now, my family own a pub and a guest house in Glaslough. When I grew up it was a mushroom farm. So that was a very exotic and arty upbringing – with all the mushrooms. It was very far from this world.”

I would guess that working behind a bar offers pretty good informal training to the aspiring actor. You get to meet new people. You get to observe their habits up close. Rada doesn’t give you that.

“Yeah, yeah, I do think that,” she says. “I was about 14 or 15 when I was working behind the bar. Now, I cite it as my training. You’ll never get a better anthropological lesson. You really get to know people in a small-town bar. In a big-city bar, people have cocktails and leave. But it’s very different in a small town.”

Wide-eyed, with a flexible, energetic voice, McKenna has the sort of presence that attracts attention. She did a bit of theatre as a kid. She somehow ended up appearing in a film that, it later transpired, was aimed at teaching Swedish kids how to speak English. But she directed most of her creative energies towards dance and music.

There is a familiar pattern to these stories. When the budding actor leaves school, he or she is immediately flung into a wretched dispute with well-meaning parents. The teenager wants to attend drama school. Mum and dad urge training for accountancy, medicine or quantity surveying.

It seems that Charlene had a very different experience.

"It was the other way round for me," she said. "They had no heed of me being a teacher. My father said: 'There's something else for you.' It was me that was accepted to dance college at the same time as I was accepted to music college. And it was me that decided to do teaching. I can rely on that, I thought. I left after two years. But I was only there a year when I got a part in Breakfast on Pluto ."

Getting that role in Neil Jordan’s take on Pat McCabe’s novel didn’t quite convince her to make the final leap towards show business. But she remembers it as an extraordinary experience. Hearing that Charlene was taking theology classes at college, the famously eccentric director spent much of the preliminary interviews discussing the life and works of Saint Thomas Aquinas. That seemed to do the trick.

“He gave me the part in the room,” she says. “Cillian [Murphy] told me to go and celebrate. So, I went to McDonald’s.”

She was then just 19. Despite the earlier protestations of her dad, she returned to college. But the bug was burrowing deep into her psyche.

“Once I had filmed that in the summer holidays it was very hard,” she says. “You spend your holidays with Liam Neeson and all these people. You then think: it does exist. This world is tangible. I can touch it. Now I am back in college. The reliability of it all was not comforting me any more.”

Happily, sometime that year she secured a role in Eugene O'Brien's TV series Pure Mule . Launched in 2005, the series set out to depict the lives of a group of young people from the Irish midlands. Far from wallowing in sleepy insularity, the scripts found the characters carousing, shagging and partying like, well, young folk in any other part of the globe (to be fair, that's not all they do). Though the first run of the series screened less than a decade ago, it already seems like something of a period piece. The economic collapse of 2008 changed everything.

“It’s hard to talk about it now,” she says. “Things really have changed. Then it seemed right on the money. Somebody stopped me yesterday to say it was a perfect representation of small-town life. I’d seen that lunacy first hand. That’s also why I got the role.”

With the return of mass immigration and growing unemployment, life in those locales looks to have slowed down. It’s the 1980s again. Isn’t it?

“It was an interesting time,” she says. “It is only now I can see that. I was only born in 1984. Our generation didn’t know anything else. It’s only now we look back and see all that.”

McKenna has worked pretty consistently since then. She played the Marchioness – a favourite role to Dickensians – in a 2007 adaptation of The Old Curiosity Shop . She has had substantial parts in such British series as Misfits , Law & Order: UK and The Adventures of Merlin . She recently left Raw , the Irish series concerning culinary mischief, after four-and-a-bit series as Jojo Harte, but remembers the production with much affection.

“Was I pushed? No, I decided to go,” she says. “We had done four and I wasn’t sure about doing any more. The show was good. I loved the character. I loved playing her. It was almost because of that I wanted to go.”

Going out on a high?

“I think: quit while you’re ahead. I love going out on a high. I respect it when shows that do that.”

Jump offered her a chance to shoot up north. It's an interesting piece. Though the picture involves gangsters, violence and mortal peril, it somehow also manages to be a celebration of the new Derry. The camera zips around a city that looks to be alive with techno-scored celebration.

“Oh it was cold,” she says. “It was soooo cold. That was that really bad winter. But that added an aesthetic layer. It was almost all night shoots, going through to six or seven in the morning. So, we had to close off the bridge. So, in that sense, we hardly saw anybody but ourselves. But nothing had been made there for ages. So there was a great deal of talk about it.”

She would have expected to return home for Jump . But Ripper Street does not, at first glance, look like it was shot in Dublin. A delightfully gothic romp, the show deals with the aftermath of the Jack the Ripper slayings in Whitechapel. Charlene stars alongside Matthew Macfadyen and Jerome Flynn (of Robson and Jerome) as a sharp-tongued prostitute.

“That was the funniest of all,” she laughs. “It was this great BBC show. I was playing an Eastender. I live in the East End. And guess what? We’re filming in Dublin. If I had stayed in Dublin would I ever have got the role? I really don’t know.”

And they won’t even let her settle in London. Now, inevitably, voices are urging her to move several thousand miles westwards.

“I come from a small town. I felt: oh I’ve conquered Dublin. Aren’t I great?,” she laughs. “Then they’re like: ‘Go to London.’ Now they’re all talking about LA. I don’t want to go. Leave me alone! Whenever I’m settled they try and make me go somewhere else.”

I'm sure she's ready for Los Angeles. But are they ready for the Monaghan whirlwind?

yyy Jump is out now and is reviewed on page 12