Siobhán McSweeney on why playing the romantic lead in Holding felt radical - and saying goodbye to Derry Girls

“We perpetuate this myth that only certain body shapes and certain classes and certain ages are allowed to lead ‘leading’ lives. The greatest subversion of all is to show the average, and I’m incredibly proud of being average.” Siobhán McSweeney takes a pause. “Note I didn’t say ‘mediocre’...”

There’s little chance of anyone reaching for that word to describe her. The actress and presenter, 42, is the star of two of our most beloved television shows, playing the formidable, eye-rolling nun Sister Michael (or “Big M”, as she refers to her) in Lisa McGee’s Channel 4 comedy Derry Girls, set towards the tail end of the Troubles, and hosting The Great Pottery Throw Down, the crafting competition that’s heart-warming, but not twee, on the same channel.

For her next role, she will star in the ITV adaptation of Graham Norton’s first novel, Holding, playing Bríd, “a very stuck woman” living in a sleepy Cork village, whose past is dredged up when human remains - thought to be those of the fiancé who left her at the altar years ago - are discovered nearby. The town’s (only) police officer, PJ, played by Conleth Hill, finally has a proper case to solve - and a tentative romantic spark develops between him and Bríd.

“She’s a romantic lead and she looks like me,” McSweeney says. “Who would have thought? That’s not normal [on screen] and yet life shows us that it is completely normal. Why are we settling with this propaganda that people don’t have romances all over the place?” She’s “hungry to see” stories about “the characters we don’t normally see or we don’t give leading parts,” presented “not in the sort of faux ‘you go girl!’ bulls**t” but with “a complexity to [their] psychology that is worth watching on a Monday night at nine o’clock or whatever.”

McSweeney grew up in Aherla, a village in County Cork, and studied for a science degree at University College Cork before moving to London when she earned a place at Central School of Speech and Drama. She’s been based here since, but “the idea of going home” to film in a place “where I have such strong memories”, especially after lockdown had prevented her from returning for so long, was “an actual dream come true” - so much so that despite breaking her leg while filming, which she describes as the “most traumatising injury of my life,” and having to spend 18 days in hospital, “it was still the best summer ever.” Her injury meant more “car acting” than anticipated. “There are scenes where I’m literally being propped up - lots of rolling down the window and leaning out.”

Her personal connection to the area, though, means she’s feeling “fierce nervous” about Holding’s release, “because I feel such a responsibility. Let’s not beat around the bush, Irish portrayal in British media has a long and complex history.” There are certain “expectations” around “what an Irish show looks like”, she notes, and the show is “almost playing with that idea of certain, I don’t want to use the word ‘stereotypes’, but certain paradigms that seem familiar, and in mean-spirited hands can be denigrated. But that tone has been specifically used to lure you in”, she says, lending a false sense of security.

Indeed, there’s a darkness and an off-beat humour to Holding that might surprise viewers. “We see certain landscapes, we hear certain notes in an accent and we think we know what it is. And then the story grabs you underneath,” McSweeney says. When she first read the scripts, she noted “something Coen Brothers, something Fargo-esque” about them, “because you’re in a world that looks and smells and tastes like the one we’re in, but it’s just a little bit different.”

At one point in episode two, Bríd announces to Hill’s character that she has “had enough shame”. That moment felt “radical”, she says, “and that is very much what I feel Ireland has been doing recently with a lot of its referenda… It’s a very interesting time in Ireland at the moment. Let’s see where we end up.” Kathy Burke, the show’s director, felt like “the perfect person” for this story, not just because “she’s London Irish” but because of her background in comedy. “You can only really get to the tragedy of things if you laugh,” McSweeney says. “We’re too smart. Now we know that people don’t really stare out of windows crying for days on end. There’s usually a fart joke in there somewhere. That’s how we live, that’s how we get through things.”

There’s something “punk” about “putting [herself] and Conleth as romantic leads”, McSweeney reckons - and there’s a similar quiet radicalness about the Pottery Throw Down, too, a show which, she says, is as relaxing and soothing to work on as it is to watch (phew). Watching her acting work back often feels a bit like “hell”, but she’ll enjoy the competition on a Sunday night with a takeaway or a cup of tea, like the rest of us, to “revisit the lovely things they’ve made.”

“Nice can be radical,” she adds. “Being mean is over - it’s very easy, it’s very basic and it’s had its moment. Being nice is not to be confused with being vapid, or not having an edge, or not being intelligent. That show is a deeply, deeply nice show, and I think that’s incredibly radical and punk.”

Before Christmas, McSweeney wrapped on the third and final series of Derry Girls, following pandemic-induced delays (“It’s going to be Derry Menopausal Women at this point”). After five years of the show, it felt “incredibly weird to say goodbye” to Sister Michael and hang up her habit for good. “I’ve never had that before - a character that you stay so long with,” she says. “I’ve also never had a character that has changed me in so many ways… That show has completely changed my life, good, bad, and different. But it’s irrevocably changed because of that mad nun.”

For her, the success of the show is “testament to Lisa [McGee]”, its creator, who she has known for years as part of “a gang of us that used to go drinking and partying.” McSweeney also appeared in an episode of McGee’s previous sitcom London Irish back in 2013 (alongside Peter Campion, who now plays Father Peter, the good-looking priest who is the target of much of Sister M’s most extravagant eye-rolling, in Derry Girls). She’s thrilled that “there’s a certain generation of young women now [for whom] Derry Girls is part of their internal landscape… That’s an incredibly special thing to be part of.”

It will certainly be a tough act to follow, though she is currently filming Disney+’s new comedy Extraordinary, which she promises has “probably the funniest scripts I’ve read since Big M.’’ Would she consider a move behind the camera, like Burke? “I would like to evolve. Acting is such a precarious job for so long… All I was doing was waiting for the next gig, not sort of allowing myself to look at anything else. So I’m at a lucky stage now… Now that I can take a breath, I can look around a little bit more. And I think that shows an evolution of thought, really.”

Holding is on ITV on March 14 at 9pm