Christopher John Francis Boone, teenage protagonist and dog death detective in The Curious Incident of the Dog in the Night Time, is not a fan of theatre. “I don’t like acting because it is pretending that something is real when it is not really real at all so it is like a kind of lie,” he explains. Yet few fortunate enough to see the National Theatre’s smash hit staging of his story could fail to fall in love with it.

Since its first London outing, Curious on Stage has gone on a journey just as remarkable as Christopher’s own, winning seven Olivier Awards for its original run (a record beaten only by Harry Potter and the Cursed Child), and snowballing into an international phenomenon. Following its first UK tour in 2014-15, Mark Haddon’s touching and highly original tale is now back on the road in Britain, heading for the Birmingham Hippodrome in July.

“As I was writing, I was thinking that this had to be a play that thousands and thousands of people could engage with,” says Simon Stephens, the playwright responsible for adapting Haddon’s novel for the stage. “It’s such a popular book because it’s so democratic. It hasn’t suffered in the literary world but it’s also unapologetic about being readable. So many people who don’t read many novels will read this and love it, and part of why Mark has been so successful as a writer is that he can write for broad audiences, kids as well as adults, so I realised we needed to do the same.”

Published in 2003, the book won multiple awards and ardent admirers across a wide a range of ages. Taking its title from a Sherlock Holmes story, it follows a determined fifteen-year-old boy conducting his own investigation into the mysterious murder of his neighbour’s dog by means of a garden fork. After a run-in with the police, his father expressly forbids him from probing any further into the matter – which of course he completely ignores. Gradually, his amateur detective work leads him to uncover a tangled web of secrets that will change his life forever.

In the book, Christopher writes down his experiences in the form of a murder mystery novel which in effect becomes Curious Incident itself. On stage, meanwhile, that book in turn becomes a play, Christopher overcoming his reservations about performance with some encouragement from his teacher, Siobhan. Though he’s never explicitly labelled with any specific condition, it quickly becomes clear that Christopher sees the world a little differently to most.

“It’s such a challenging role,” says Birmingham-born Sam Newton, who shares the part of Christopher with Scott Reid in the current UK tour. “There is the element of autism but we’re not labelling the show in that way – we’re approaching it from the angle of character. Christopher has quite a strict set of rules about what he likes and what he doesn’t like, and that’s where we’re coming from rather than scientifically studying autism and how to play that.

“There’s a lot of trying to work out what everything means for Christopher and I love the way that his brain works,” he adds. “It’s very logical where he ends up after thinking everything through, which is great. It makes total sense how he gets to where he gets.”

Associate Director Elle While – also a native West Midlander – agrees.

“When I’m casting this, I’m really interested in the heart of the person auditioning, because whoever they are, what we see on stage will be their version of the character,” she explains. “I look for actors who are incredibly generous hearted. Because Christopher is in some ways so difficult as a character, we have to get someone who people will love no matter what he does.

“Sam has got a real simplicity with which he approaches the text,” she continues. “Sometimes actors will come into the room and they’ll try to show me that they can do autism or whatever, but I’m really interested in people who can strip all that away and just tell the story through the character. Sam has that focus and clarity.”

If believability is Christopher’s main beef with the idea of performance, then Curious would certainly be high on his list of offending shows. Though it’s highly stylised, its clever design, subtle staging rules and innovative special effects work together to immerse us completely in Christopher’s world, offering unique insights into his thought processes. The square, neutral-coloured, almost clinical or mechanical looking set is like a visualisation of his brain, items popping in from various places like sudden thoughts. Meanwhile, supporting cast members must be invited in by Christopher rather than opening doors and walking in and out at leisure.

Later, when he ventures out alone to catch a train from Swindon station, flashing lights combine with layered sounds and video footage to reflect the sensory overload that he experiences in this bustling and unfamiliar setting. But for all the spectacle and visual magic, Stephens insists, it’s still the quality of the storytelling that really brings the character to life.

“When I first talked to Mark about the design, we had a conversation about Simon McBurney’s A Disappearing Number, which was an extraordinary kind of high-tech video art piece, which he was thrilled by,” he recalls. “He was talking about using all this three-dimensional video stuff and I said, ‘Mark, you can’t. This has to be a play that can be done in classrooms and amateur dramatic groups.’

“As it happens, Finn Ross who worked on A Disappearing Number also designed Curious Incident, so Mark got his way. But you know, we did a run at Stratford Town Hall without any of the video or technology, and it was really great. So I think the play stands up without any of that. I’ve been to schools throughout the country and seen how kids do very tricky bits, like the journey from Swindon to London, and they’ve just got to bring their imaginations to it.”

Whatever techniques are used, it’s ultimately the commitment to finding creative ways of conveying Christopher’s individuality that allows audiences to hone in on universal elements of the story: the fear, betrayal, anger, love, courage and resilience that he feels at various points in his adventure are things with which every one of us can identify.

“I think this is a story about England and its sense of self as much as anything,” says Stephens. “For me, Curious Incident is a story about kindness and bravery, and I think there’s never been a more important time to tell a story about our country which celebrates its capacity for those things.”

It’s in part for this reason that the show is extending its reach beyond London and out into the country as a whole. As Stephens points out, most of the story itself is set in Swindon rather than London, but there’s a bigger context here too. Curious is just one of four National Theatre shows to be heading out on tour this year (along with Jane Eyre, War Horse and My Country; a work in progress), as part of a new UK-wide focus from National Theatre Artistic Director Rufus Norris.

“I think more than ever there’s a feeling in this building that our work needs to be about getting out across the country rather than staying on the Southbank,” says National Theatre producer Kash Bennett. “We’re the National Theatre, not a London theatre, and I think everybody feels very strongly that we have a real responsibility and a need to be taking shows out everywhere from Aberdeen down to Plymouth.”

The Curious Incident of the Dog in the Night Time is at Birmingham Hippodrome Tuesday 4 – Saturday 8 July.

By Heather Kincaid