Is Best Interests based on a real story? Everything you need to know...

Is Best Interests based on a real story? Cast standing outside a courtroom.
Michael Sheen and Sharon Horgan star as Andrew and Nicci Lloyd. (Image credit: BBC)

BBC One's powerful and poignant drama Best Interests looks set to be one of the most memorable TV events of the year, striking a chord with viewers and critics alike. 

Created by BAFTA-winning screenwriter Jack Thorne, who has previously won acclaim for Help and National Treasure, the four-part drama tells the story of a couple's battle to stop doctors from turning off their daughter’s life-support machine

Sharon Horgan (Catastrophe) and Michael Sheen (Good Omens) star as Nicci and Andrew Lloyd, whose 13-year-old daughter Marnie (Niamh Moriarty) has Congenital Muscular Dystrophy, a rare and life-limiting condition that has left her needing constant care.

However, when Marnie's condition deteriorates, her parents are devastated when doctors suggest it’s in the teenager's best interests that she be allowed to die. 

They argue the 13-year-old is in pain and her treatments are becoming too invasive, yet Nicci and Andrew believe Marnie has a life that’s worth living and begin a battle to keep her alive that leads all the way to the high court. 

With plenty of dramas inspired by real-life on our screens in recent years, we wondered whether Best Interests might also be based on an actual case. Here is everything you need to know... 

Best Interests

Jack Thorne says the four-part series was not based on a real case (Image credit: Getty)

Is Best Interests based on a real story? 

No, screenwriter Jack Thorne says Best Interests is a work of fiction...

"I didn't want to tell the story of a real-life case because it didn't feel appropriate," he explains. "I wouldn't want to tell the story of a real couple and a real family going through this, I think it would be too intrusive. I've told real stories in the past and I've told stories that tried to replicate real stories, or tried to get inside the same truth, the same questions within those real stories, so we spent a lot of time talking to people that have gone through this kind of situation and doctors who've experienced it.

"As soon as you go into real-life cases you have a responsibility to the people whose story you're telling. As a dramatist, you're constantly asking the question of how to get to the truth of something, right? That's what you want, you want the truth of something. That's a really obvious thing to say but if you are dealing with their truth — of a real-life case — and you are responsible to their truth, sometimes you can't get involved in the truth of their central problem.

"And so with National Treasure, with Kiri, with this, it's a way of finding that truth without feeling an obligation to anyone else. That makes it sound really callous, but I hope it means that in some ways you're able to be more compassionate. Because you're not protecting anyone, you're just protecting the truth of a situation."

For some, the series is reminiscent of the case involving Archie Battersby, a 12-year-old boy whose life-support machine was switched off last year after a legal battle that went on for several months. However, Best Interests was written and began filming before that case went to court. 

"Inevitably, the case with Archie, having already done the story, brings it all back," says Michael Sheen, who plays Andrew Lloyd. "You just can't help but feel like you have a bit more of an insight into what the family might be going through. But that's the other I'm sure very difficult thing if you're actually going through it — everyone's got an opinion. 

"All the way through making this, every day hearing about it I just felt for the parents and the family and how impossible it is to be in that situation. Before we did this piece, when similar cases came up, I would probably have had a stronger sense of what side of the argument I was on, or whatever. But not at all anymore. You just feel for them."

Best Interests

Best Interests is not based on a true story.  (Image credit: BBC)

What condition does Marnie have in Best Interests?

Thorne, who suffers from cholinergic urticaria — a condition that makes people allergic to outdoor heat, artificial heat and their own body heat and causes chronic pain — has long been an advocate of disabled causes. Yet he and producers spent many hours deciding which condition Marnie should have in the series, so the four-part drama would not be compared to real-life cases. 

"We actually spent a long time talking about different conditions," he explained. "And there was partly a need to not replicate other conditions in the press. We didn't want to directly represent anyone else so that they felt like they were that it was their story being told." 

Best Interests premieres on Monday, June 12, 2023 on BBC One at 9 pm. 

Sean Marland

Sean is a Senior Feature writer for TV Times, What's On TV and TV & Satellite Week, who also writes for He's been covering the world of TV for over 15 years and in that time he's been lucky enough to interview stars like Ian McKellen, Tom Hardy and Kate Winslet. His favourite shows are I'm Alan Partridge, The Wire, People Just Do Nothing and Succession and in his spare time he enjoys drinking tea, doing crosswords and watching football.