“It’s something that David Attenborough has never told us about, which is a disgrace,” laughs author Kes Gray, discussing the massively successful Oi Frog! series of picture books he creates with illustrator Jim Field. “If you rhyme with something, you sit on it; those are the rules that prop up the animal kingdom!”

The Oi Frog! picture books – which also include Oi Cat!, Oi Dog!, Oi Duck-billed Platypus! and the recently released Oi Puppies! – are a global rhyming phenomenon. They began with, as Gray puts it, the “cliché that underpins so many childhoods” that frogs sit on logs and cats sit on mats. From there, Gray and Field tried to explain to the world where other animals sat in this realm of rhyming recliners.

As ever, the simplest ideas are the best, and the series has now sold more than a million books. It’s an image that even illustrator Field can’t quite picture: “I keep trying to think of it as if it’s a massive stadium full of people holding a copy of the book, then doing that ten times over.”

What’s more, Frog, Dog, Cat and their chair-shunning chums come to life on stage in a new production produced by Kenny Wax Family Entertainment, the company behind theatrical translations of The Worst Witch, Hetty Feather, and more, and the show is coming to the Radlett Centre from Monday, June 8, to Thursday, June 11.

“We didn’t see it coming,” admits Kes. “When we were asked ‘Can we put it on stage?’ I thought, ‘I don’t know, can you?’ We certainly don’t know because we don’t create theatre, we create books.”

“It’s amazing to see what’s happened,” adds Field. “If you adapted it directly from the books, the show would only be about 15 minutes long, so they’ve created a backstory around the characters. There’s a whole life for Cat that we never knew about. It really has given it a new life and greater depth. And all the songs they’ve come up with as well!”

The stage adaptation mixes drama, puppetry, jokes, rhymes and songs as it draws from the first four books to tell its story of a day at Sittingbottom school, where chaos reigns when Frog decides he might not want to perch his bottom on a log.

The quietly spoken Gray and Field are very calm and laidback as we discuss this new project.

“We know the medium of the books,” Field explains, “but theatre is a different medium, so we have to let somebody else run with it where they have the expertise. We were involved at the early stages, but we’ve let the people who know what they’re doing bring it to life.”

There may be some truth in that, but it doesn’t take long to discover that both Oi! creators have definitely been keeping an eye on proceedings with the new show.

Gray has focused on the narrative and chronology of the piece to ensure they don’t disappoint a young audience, “who are super bright and will know instinctively whether what a character says is true to them.” Field, meanwhile, has been similarly obsessed with the minutiae of puppet eyebrow placement.

“I think it’s my job to ask ‘What about this? What about that?’”, Gray says. “But all concerns go away when it becomes collaborative, and this has been collaborative from day one. And lots of fun. They know what they’re doing, so Oi Frog & Friends! is a lovely balance between what the books have to offer and what a stage performance has to offer.”

It’s a particularly exciting time for the writing team who, slightly disappointingly, are both sitting on chairs rather than anything rhyming. Surely Kes should be on a fez and Jim should lounge on a hymn? As well as the stage adaptation, they’ve also released the latest book in the Oi! series, Oi Puppies!, which follows a similar trajectory.

“We’ve been really lucky,” admits Gray. “We’ve had so much support from booksellers. There’s just something about Oi! that everyone embraces and runs with. Teachers like it, librarians like it, children like it and parents like it because they can read between the lines and they know when we’re being tongue in cheek.”

Gray and Field were thrilled to first see the show live on stage at its successful West End premiere in December 2019, prior to the UK tour starting in February 2020. Gray reckons “it has taken the Oi characters to places I could never have imagined. The fun, the artistry and the sheer theatrical genius of this production is something to behold!”

Field adds: “Seeing the characters brought to life was both surreal and incredible. Oi Frog & Friends! bounces along with non-stop energy, amazing puppets, funny songs, shouty rhymes, and a squirty elephant trunk. It’s brilliantly bonkers!”

“I think children experiencing as much culture as they can is a great thing,” Field says. “Reading is absolutely essential; parents should be reading to their children every night. And I remember what it was like seeing brilliant Christmas pantos.”

“I think it’s important for children to do things that take their minds in different directions,” Gray concludes. “There’s something wonderful about going to the theatre; it kind of hugs you. You get in, and you don’t want to leave.”

The Radlett Centre, 1 Aldenham Avenue, Radlett, Monday, June 8, to Thursday, June 11. Details: 01923859291 radlettcentre.co.uk