WHEN actor, humorist, author, Channel swimmer and activist David Walliams was a child he spent lots of time with his grandmas.

So began his odyssey to writing Gangsta Granny, his book for children that has since transferred to the stage in Birmingham Stage Company's touring production, whose next destination is the Grand Opera House in York.

"Sometimes I would selfishly think spending time with my grannies could be boring," he says. "But when I got them on a subject like living in London during World War II, when bombs were raining down, they would become very animated and I would be enthralled. I realised everyone has a story to tell."

In Walliams's tale, Friday night means only one thing for Ben: staying with Granny, where he must put up with cabbage soup, cabbage pie and cabbage cake. Ben knows one thing for sure – it’s going to be so boring – but what Ben doesn’t know is that Granny has a secret. Soon Friday nights will be more exciting than he could ever imagine, as he embarks on the adventure of a lifetime with his very own Gangsta Granny.

"There was definitely a smell of cabbages in one of my grandmas' houses," recalls Walliams, giving an insight into his inspiration for Gangsta Granny. "The other did break wind like a duck quacking when she walked across the room."

York Press:

Gangsta Granny author David Walliams

He acknowledges the special bond between children and their grandparents. "I think grandparents love being grandparents because they get to give the children back to the parents! Children love spending time with their grandparents because they love hearing their stories and being allowed to stay up past their bedtime," says the 45-year-old Little Britain and Partners In Crime television star.

He is delighted that Gangsta Granny has become a stage show. "It's a huge thrill seeing Gangsta Granny have this whole new life on the stage. It's already been a TV film. People seem to really like the story," says Walliams. "n fact Gangsta Granny is my best-selling book by far, and having seen the first night at Birmingham last December, I think it’s a brilliant show – better than the book."

Assessing the potential challenges or difficulties in staging Gangsta Granny, he says: "There is lots of action, especially when they try to steal the Crown Jewels. It's quite a challenge for Birmingham Stage Company to bring those scenes to life but they do it so well," he says. "Shows for children need to be fun and fast paced, which Gangsta Granny certainly is."

He particularly likes how the characters of Ben's mum and dad work on stage. "Their obsession with ballroom dancing is very funny, brought to life in the play," says Walliams, who first saw the Birmingham company in one of their Horrible Histories shows, which made him keen to work with them. "I loved the humour and the interaction with the audience so I look forward to seeing more of that.

York Press:

Oh no! Gangsta Granny's cabbage soup...again

"The great thing about seeing Gangsta Granny on stage is you will get to share it with an audience. So hopefully you will laugh and cry along with everyone else. That's what makes theatre so special."

What does Walliams hope children will take away from watching Gangsta Granny in York next week? "The moral of the story is, ‘don't assume old people are boring just because they are old’," he advises. "In fact they are likely to have had a much more interesting life than yours. Talk to old folk, listen to their stories. They are bound to be full of magic and wonder."

Wise words indeed from Walliams, who took up writing children's fiction a decade ago. "I had an idea for a story: what if a boy went to school dressed as a girl? I thought it would be a thought-provoking children's book. That became The Boy In The Dress, my first of eight children's novels," he says.

"The only limitation in a children's book is your imagination. You can take children on magical journeys in books that many adults would be reluctant to go on."

Walliams highlights the challenges presented by writing for children? "Children love to be scared but it can't be too horrifying. Children love to laugh but it can't be too rude. You always have to be the right side of the line," he says.

Earlier this week, Tuesday marked the centenary of the birth of Roald Dahl, arguably the 20th century doyen of children's authors. "I think Dahl's books always feel a little bit forbidden. He manages to balance the humour and scary elements in his stories perfectly," says Walliams, who picks The Twits as his favourite Dahl story. "It's utterly hilarious and I love that it's a children's book with no child characters."

He recalls enjoying other writers, such as Dr Seuss, in his childhood days. "I loved Dr Seuss books as a child, especially Green Eggs And Ham. His books are like nightmares come to life. They are rich and strange and utterly unlike anybody else's work," says Walliams.

David Walliams has become popular in his own right as a children's author and ticket sales for Gangsta Granny testify to that popularity. "I imagine children like the humour and that I don't patronise them," he says, summing up his appeal as a storyteller. "I deal with quite big topics, cross-dressing, homelessness, grief. I know children are a lot smarter than most grown-ups think."

Birmingham Stage Company present Gangsta Granny at Grand Opera House, York, from September 21 to 24; performances at 1.30pm and 7pm, Wednesday; 10.30am and 7pm, Thursday and Friday; 2.30pm and 7pm, Saturday. Box office: 0844 871 3024 or at atgtickets.com/york