‘I felt seen and understood’: Irish teenage actor with cerebral palsy Niamh Moriarty on starring in new BBC drama

The Dublin actor stars alongside Sharon Horgan and Michael Sheen in Best Interests

When 16-year-old Niamh Moriarty first read the script for Best Interests, she felt “seen and understood”.

Moriarty, from Killiney, Co Dublin, stars alongside Sharon Horgan and Michael Sheen in the BBC One drama series which starts on Monday, June 12th. She has cerebral palsy and plays a disabled character. “I have never seen anyone attempt to recognise those struggles before,” she says of Bafta-winning writer Jack Thorne’s screenplay.

Another Irish actor, Alison Oliver – who played Frances in the TV adaptation of Sally Rooney’s Conversations with Friends – takes the role of Moriarty’s on-screen sister. Her character summarises the moral quandary of the show in its first episode: “How can you let go of someone who still laughs?”

Thorne (known for Wonder, Enola Holmes and His Dark Materials) has turned his attention towards a complex issue few can imagine enduring. Marnie (played by Moriarty) has a condition which limits her life expectancy. A smiling, beaming child on-screen – on her good days you’d hardly know her form of muscular dystrophy is particularly severe. But after an episode prompts hospitalisation, doctors believe it is in her best interests to be allowed to die – a recommendation her parents (played tenderly by Horgan and Sheen) refuse to accept.


In the opening to the first episode of the four-part drama, viewers are teased with what appears to be a nationwide furore in the UK over a legal case only briefly alluded to before jumping back to the start.

Marnie’s rich and joyous life has distracted her parents from the initial warning they received when she was a baby, that they must prepare for the possibility her life would not be a long or full one. With each infection worse than the last, she never returns to the same health as before. Now arises the question: at what cost should treatment continue if that life is characterised by little else than bouts of severe pain – even if there is laughter in between?

The emerging tragedy is the divergence of perspectives from Marnie’s parents about what’s best for their daughter. As one faces up to the reality of the situation, the other appears adamant about the life still within the child despite all the pain life itself entails.

Moriarty was delighted to be part of a cast with other Irish actors.

“It was quite nice to know that playing my mum would be a brilliant, iconic, Irish lady [Horgan],” she says. “I often just found my mouth on the floor just trying to take in all of their expertise.

“We became like a family pretty much from the moment we met. With Sharon, Alison and myself all being Irish, we had an instant connection. Sometimes I would look down at the call sheet in the morning and I would just be amazed that my name was alongside theirs. They are utterly fabulous individuals.”

Just to see the look on their faces when I would come out on stage and they knew they were represented up there, that meant enough to me

Authenticity was key to the casting of Marnie from the beginning, says Moriarty, who recently finished transition year. Moriarty was born three months early and says her brain didn’t send the correct messages to her muscles from the waist down, affecting muscle tone and function. At the age of six, she underwent life-changing surgery that removed tightness in her muscles, granting her more freedom than ever before. Growing up, she never saw children like herself on screen. At the age of 11, she set her sights on drawing from her own experiences and becoming an actor herself.

“I find that when I watch a disabled actor playing a disabled person, there’s a certain understanding and realism in their performance that just can’t be captured by someone who hasn’t gone through that experience themselves,” she says. “On-screen roles for disabled actors are so few and far between that, quite frankly, I think we should be given the chance to take them when they come – because they’re not always there.”

Moriarty was recently cast in RTÉ's Toy Show the Musical and says children with various disabilities would often thank her after the show: “Just to see the look on their faces when I would come out on stage and they knew they were represented up there, that meant enough to me. If I had seen that when I was a child, it probably would have changed my life.”

Where few have been granted the opportunity before, she hopes to carve a path for young actors with disabilities to follow suit.

I think from that moment when I heard about the difficulty the production crew faced in acquiring it, that’s when I decided I was going to change that

She previously played Tiny Tim in the Gate Theatre’s 2019 10-week run of A Christmas Carol (scripted by Thorne); has starred in a short film; voiced characters in Riverdance: The Animated Adventure on Netflix; and will play a role in Silver, an upcoming young adult fantasy film for Amazon Prime. But Best Interests is her biggest role to date, and she’s keen to use the opportunity to highlight issues in the industry.

“When I got the first audition for Tiny Tim, Jack [Thorne] had been very specific about Tiny Tim being cast as a young disabled actor,” she says. “That’s the first [time] I’d come across a casting call like that in my career.”

When Moriarty was cast in Best Interests, she was met with an enthusiasm to cater for her accessibility needs she had not previously encountered in the industry. At the time of filming in spring 2022 (she returned from shooting in London just a week before sitting her Junior Cert exams, in the middle of her “post-show blues”, she says), Moriarty had the only wheelchair-accessible trailer on a UK set at the time.

“I heard them say that, and it shocked me. I think from that moment when I heard about the difficulty [the production crew] faced in acquiring it, that’s when I decided I was going to change that.”

Since then, Thorne and other creatives in the UK have spearheaded the charge to transforming the industry for disabled people. The TV Access project, which aims to see full inclusion of disabled talent by 2030, has already received commitments from the biggest studios, such as the BBC, Channel 4, ITV, Amazon, Disney, Netflix and Sky. But Moriarty believes such transformations should not be limited to the UK, and she intends to do her bit when it comes to “bringing some of that to Ireland soon”.

“At the end of the day, the stories that we tell are about the real world, which is full of a diverse collection of human beings,” she says. “I think there’s a space for everyone in storytelling.”

Best Interests begins on BBC One on Monday, June 12th at 9pm