Tabby McTat: Julia Donaldson and Alex Scheffler discuss star-studded BBC adaptation narrated by Yorkshire's Jodie Whittaker

Spanning three decades, the duo have given the world such classics as The Gruffalo, Room on the Broom, Stick Man and Zog, and with them, some of our best loved children’s fictional characters, which have been turned into animated TV classics.

This year’s BBC adaptation follows the adventures of tuneful Tabby McTat and his busker friend, Fred. Based on the eponymous book by former Children’s Laureate and acclaimed author Donaldson, it has all the elements that catapulted her stories to the stratosphere: sing-song, melodious rhymes, a journey of adventure with challenges and eventual resolution, and a story as satisfying for parents to read as for children to hear.

This year marks the 30th anniversary of the collaboration between Donaldson and Scheffler – and yet, for one of the most successful creative partnerships of today, the pair are pretty nonchalant about it.

They are bemused by questions about their decades-spanning work together, Scheffler simply shrugging and answering “we don’t really work together”.

“We don’t have anything to do with each other,” continues 75-year-old Donaldson. “And I’m not joking – we work completely separately. And we don’t even really talk about the books when we’re together.”

“We’re being kept apart because we would have arguments all the time, and fights, and crossed swords,” jokes Scheffler.

Jokes aside, the Tabby McTat picture book, published in 2009, introduced a new cohort of cherished characters to the Donaldson-Scheffler canon. It is a poetic story of love, difficult choices and adventure.

Tabby McTat and Fred’s musical friendship is ruptured when Fred chases a thief, breaks his leg and is whisked off to hospital, leaving Tabby McTat lost and alone. Tabby then meets the slinky Sock, falls in love and has babies. And when Fred reappears, Tabby is confronted with a difficult choice and torn feelings between two homes and two families.

It is a more complex story, and consequent lesson, than other Donaldson books. “It’s the most complex one in a way because it’s about a character who’s torn between two completely different lifestyles which can’t co-exist,” explains Donaldson. “In most picture books, you know what the principle character wants and you know they’re going to get it at the end but you’re not quite sure how, whereas in this book the principal character didn’t quite know what he wanted.

“But I think there are probably lots of children who have to make choices and are torn. There’ll be children whose parents are separated and are torn between two homes, and that is something that children will relate to.”

Scheffler says Donaldson’s stories are often about “being lost and being found, and about solidarity, helping others, caring for others”.

“I think there’s a lot of that in her stories and it’s in a very subtle way. And I like that.”

To imbue his characters with personality and expression, Scheffler, 65, says he anthropomorphises. “Children have to be able to read the expressions of the cat, so they have to not just be cat expressions but also be read as human expressions. That’s the secret.”

Doctor Who’s Jodie Whittaker, who hails from Skelmanthorpe, which is between Barnsley and Huddersfield, narrates the animated film while Gavin and Stacey’s Rob Brydon plays busker Fred and Gangs of London’s Sope Dirisu is his tuneful feline, Tabby McTat. Also among the cast are Peep Show’s Cariad Lloyd, The Thick of It’s Joanna Scanlan and Enola Holmes’s Susan Wokoma.

Wokoma, 35, who voices Sock, believes that “at the crux of this story is compassion for everybody”.

“It’s about family,” she continues. “And also about loss and searching and loneliness. And I actually think the part of Sock is quite complicated – because Tabby loses his parent, he finds somebody else, a partner, and then there’s that kind of back and forth and that conflict of, ‘Do I stay? Am I happy? And I miss home, but I don’t miss home, and I love this’.

“So, I think Sock’s part of it is all about change and embracing change and not being scared of change – allowing it to happen and allowing yourself to breathe and find a new family. It’s that conflict but also the resolution that change is a good, happy, safe thing. It’s OK.”

Before Donaldson stepped foot into the world of publishing, she was a songwriter. In fact, as part of her French course at university she spent some months in Paris where she started busking, initially with friends and then with her future husband, Malcolm.

“A girlfriend and I used to sing things like Plaisir d’amore and Greensleeves and we’d only play about three chords,” she relates. “But we had this medic friend, Malcolm, and he suddenly wrote to us with this really long list of songs: Beatles songs, songs from the musicals Hair and Oliver! And then he came up to join us and we took the Champs-Elysees by storm.”

As soon as Donaldson had landed on the protagonist as a tabby cat, she knew his friend had to be a busker.

She grappled with his signature song for a while – but one Sunday tinkering on the piano, it slotted into place. ‘Me, you and the old guitar/How perfectly, perfectly happy we are/MEEE-EW and the old guitar/How PURRRR-fectly happy we are.’ And the result is a ditty that remains in your head long after you cease to hear it.

Tabby McTat is on BBC One on Christmas Day.