On the surface, the hour-long Blue Remembered Hills is just a group of seven-year-olds in wartime Britain playing in the sunshine. But it isn’t long before their childlike teasing turns to bullying and fighting, and things quickly spiral out of control until tragedy strikes.

Dennis Potter’s groundbreaking play, written in 1979, still has the power to shock with its exploration of cruelty and lost innocence. Yet it is also funny, charming and nostalgic, and Psyche Stott, director of the current touring production by Northern Stage, dismisses the idea that the play’s central themes are bleak and disturbing.

“There’s great joy in it,” she insists. “There’s something that children have that we have lost and that’s to be open to possibility, and through that some fantastic moments of joy and real connections and friendships are made through the hour of play.

“Children don’t sit round the edge of the pool to see if the water’s warm enough to climb in – they jump in the deep end and then see if they can swim. As we get older, we become more hesitant and more cautious. “It’s interesting why he’s used children to explore the way people communicate and interact with each other. It’s very universal, and from the audiences that have seen the show so far, they have seen themselves and elements of their friends in the characters onstage.”

One of the fascinating things about Potter’s play is the way we, as adults, are effectively looking through a window at a child’s world, and it’s a world that seems to resonate with a lot of people.

“What’s lovely is that within five seconds of the play starting, every time I’ve seen a performance of it, the audience have found something in that first movement of that first character that has made them laugh,” Psyche says. “And it’s not one specific age range. We did a matinée in Liverpool, and it was wonderful to look round the auditorium and see every sort of person represented in terms of age range, all finding something in the play that connected with them.”

Potter’s decision to have the children played by adult actors was revolutionary back in the late 1970s. So how well does it work?

“I think it works brilliantly,” Psyche says. “When you see children on stage, there’s a way they behave in front of adults to get approval. He didn’t want the audience to sit back and see seven-year-olds looking cute, because then they’re seeing children acting.

“By having adults playing the children, the trick is to completely take that on board straightaway, and then you really see the children.”

Blue Remembered Hills was conceived for the small screen, so adapting it for the stage has, Psyche admits, been challenging. A simple set, together with clever use of lighting, allows her to create the illusion of characters moving quickly from one location to another. “The thing about theatre is it really enables the audience to participate in a way that you can’t when you’re watching television,” she says. “Like a good book, it allows the imagination to work, which is important.”

For Psyche, who trained at the Young Vic and the National Theatre before gaining directing experience with Northern Stage in Newcastle, returning to the company for this play has been a complete joy.

“It was in Newcastle that I really learned the craft of what we do, so I couldn’t be happier, to come back and work with the team that taught me everything I know.

“The cast are remarkable. They’re one of the most brave, most talented and most instinctive companies I’ve ever worked with, and I’m so thrilled at the response they’ve been getting.

“It’s a really fine line to play a child, to get it right and not to caricature. The trick is almost to not play them as children, because if you do that then you’re underselling what children are. That’s really the secret, which this cast has completely embraced.”

Oxford Playhouse Tuesday to Saturday Box office: 01865 305305, oxfordplayhouse.com