When Julia Donaldson lays out her books, they comfortably cover the capacious sofa in her sitting-room. Nearly 40 of them, their bright colours catching the eye before curiosity is sparked by titles like The False Tooth Fairy, The Gruffalo, A Squash and a Squeeze.

The last-named is special to her; it made a successful author out of a song-writer. She had always been handy with a guitar and a lyric - she busked for francs as a student in Paris. Her dramaFrench degree completed, she started writing songs for children’s television in the 1970s, and producers soon found that with her sense of fun and lyrical gift came a willingness to “write to order”.

“Whenever they couldn’t write a song themselves, they would ask me to do it. In a programme called Thinkabout Science, they commissioned 17 songs from me on everything from guinea pigs to space travel.”

Of the 100 songs she wrote, one in particular was remembered by a young mum who had watched it at home with her toddler. A year or so later, back in her publishing job, she contacted Donaldson, and asked if she could turn A Squash and a Squeeze into a book. And the rest, as they say, is her story.

But it was The Gruffalo which won her this year’s prestigious Gold Smartie award for children’s literature, after the book was nominated by school children throughout the UK.

Now her success as a writer takes her into schools where, as a mother, an actress, a qualified teacher and a gifted enabler, she seems in her element. To the schools, however, she is none of these things. To them she is “a Writer”, and schools have preconceptions. The children are often patently disappointed because, although she is a writer, she hasn’t written Goosebumps or Star Wars. Teachers have been known to assume that she writes from 9 to 5, getting callouses on her fingers and fits of depression. Shamefacedly, she has to admit that she can go for weeks, months even, and never put pen to paper.

In fact, only two days of her week are for writing and school visits. From Wednesday to Friday she is writer in residence in Easterhouse, “increasing literacy levels, building self-confidence in primary and secondary children through creative writing, and helping adults to find employment and influence their community,” she explains wryly.

In Easterhouse, the “writer” label is very useful: to the schools she is a fellow author for the children, not just another English teacher with writing exercises. The two jobs are different: Easterhouse is a three-year appointment, long-term, all about following through; in schools she can be a firework for an hour.

I watch her fizz and sparkle in Knightswood primary in Glasgo, starting with a song, written for a television programme several of the P2s had watched.

Credentials established, she shows the class the difference between poems, stories and plays by brilliantly improvising one of each around the name of a boy in the class.

Then comes the all-dancing, all-singing performance of A Squash and a Squeeze, with herself as the Old Woman, the best reader as The Old Man, and the rest of the class the farmyard animals (chicken, cow, goat and pig) and the cottage.

Learning outcomes pop up everywhere. She remembers an occasion on Glasgow’s south side, where the Old Man was being read by a Moslem boy, and they both became aware that “pig” was coming up. “Pigs are taboo in ‘educational’ books, though they’re all right in ‘trade’,” she tells me. She suggested he change parts, but no, he had a better idea, he would say “kangaroo” instead. She quickly thought of another rhyme, the class learned something about plural cultures, and social inclusiveness was preserved.

She handles the class participation very easily. A decade or so ago, she was a “young mum”, volunteering to go into her son’s school to help with the reading. Typically, she would take a group off to the cookery room, and try to listen to one while the others, idle and bored, made malarkey. So she went home and wrote little plays, with parts for everyone, and everyone appearing on every page. Everbody read every part, then she cast the parts for them to practise before they went back to read it to the rest of the class. Motivation and opportunity won the day and, when publishers started looking at her work, nine of these scripts made it into print.

Back at Knightswood, after some quiet moments learning about publishers and illustrators, she launches into a brilliant performance of her award-winning Gruffalo, playing the mouse, owl, fox and snake as if she were on stage.

Finally, as always, it is Question Time. The Knightswood class asks some serious questions - one child wants to know if she ever meets any other writers - but more and more hands are going up with the same question time after time: “Will you read us another story?” She doesn’t think there is enough time, but the class teacher nods happily, so she valiantly launches into Monkey Puzzle, a story of a lost mother with a happy ending, that has the class lumbering like elephants, hopping like frogs, slithering like snakes.

“There! You’re the first children in the world to hear that story! This book isn’t in the shops yet!” Question Time usually has its surprise.

She recalls one school where P3 got very concerned about money: “What would you do if your money was stolen?” “My husband would keep me, he’s a doctor.”

“What if he lost his job?” “Then I’d go back to busking.” In some ways, she already has.