"If we change history and we don't have smoking and we don't let women be what and who they were, then what are we going to do with the rest of our history? I feel very passionate about this and, in this country now, we're almost forgetting - heaven knows how – things like the Good Friday Agreement [a mainstay of the Irish peace process] and we could be about to throw it all away to have war again."
Gardner has a similarly ardent stance on sanitising traditional fairy tales to make them more acceptable to modern times.
"Every princess must be feisty and kick-ass and give her cardboard cut-out prince a royal bollocking but these are fairy tales, which allow for imagination," she says. "The child can be the prince or the princess and he or she doesn't have to say which one they are.
"It allows for role-playing; if you make every princess kick-ass and whatever, there's no room for these imaginary thoughts. We curtail imagination again. If anybody bothered to look at the history of fairy tales, they would see how dark they really were."
Which brings us back to why Gardner, now in her mid-60s, writes for young readers then moves into a whole other genre. Firstly, she likes writing for children who, she says, have greater imaginations because that hasn't been conditioned out of them and, secondly, she enjoys being able to use her own imagination and do something different.
Variety is, after all, meant to be the spice of life.
If the cab driver is raising an eyebrow, he's likely to have been more intrigued by Gardner's earlier remarks about her background because it is truly quite remarkable. As a school girl, she was dubbed "word blind" and cycled through various schools – none of them worked out – eventually ending up at one for maladjusted children. She concocted stories and told them to herself over and over, usually along with the mantra "I will show you, I will show you." Gardner says she knew she wasn't stupid, despite being repeatedly told otherwise, and it was more a case of not being able to "crack the code".
She loved listening to Radio 4 – "it had the most amazing programmes on it that started with the premise you were intelligent" – and audio books as well as going with her mother to the theatre. Aged 14, Gardner finally managed to "crack the code" and read her first book, Wuthering Heights, which was partly responsible for her being at a school for maladjusted children.
"This is quite a sad story," she says, "I was at a school for very 'nice' girls who wore shiny, shiny shoes and I only lasted six weeks. One of the reasons that I was finally expelled was because they thought I was mad; I tried to read Wuthering Heights and I thought it was about a toy box with all the dolls trying to get in through a closed window. Because I couldn't read it, I just heard about a box and someone knocking on the window and shouting, 'Can I come in?' and I thought, 'Well, that must be the dolls!'
"They used this as an example that I was totally unteachable and, not only that, suggested I perhaps wasn't all there with the plan. Well, when I ended up in the school for maladjusted children – and it was so dire – but there was this whole omnibus of the Bronte's and I picked it up and, for me, it was first time I had ever read. Suddenly everything went quiet, I was on the moor and it was snowing and I was cold and I found the house and the story began. I loved it, I absolutely loved it."
There was no stopping Gardner. She thought about going to university but ended up at art school instead, eventually graduating top of her year with a first-class honour's degree and a job as a theatre set designer.
She credits theatre for teaching her how to write and says when anyone asks her what university they should go to, to become a writer, she tells them to start working in theatre because you'll learn about the development of character, place and emotion. You'll also get to see the reaction of an audience.
"Unfortunately, a lot of writers write alone and they never get to see their audience fall but with theatre, you really do. You really know when a play has died, so that is something quite important because it reflects in writing."
After 15 years, and continual struggles with reading set plans and directions, Gardner switched to illustrating books and befriended an editor who suggested she should try writing. Gardner says her first reaction was to dismiss the idea as preposterous but she was told being "word blind" was no bar to being a writer.
"When I say I'm severely dyslexic, I don't do it for a, sort of, 'Oh look at me, I'm writing thousands of books!' I still am severely dyslexic and I need a ramp into the building and that is the truth of me," she says.
"I write on a laptop with a word recognition program now; I get my chapter absolutely as I want it then I send it to my editor, Jacqui Bateman, and we do what's called live editing where she reads it back to me; I'll alter or change it. She'll suggest something; I'll say yes so the live editing, for us, is an important part of the process but the ideas, they are absolutely all mine! Every single one of them and I write all the words. They're all mine."
•Sally Gardner is a guest at this year's Auckland Writers Festival while her latest book, written as Wray Delaney, The Beauty of the Wolf (Harlequin, $35) is out next month.
