Esio Trot was published in 1990. The last of Roald Dahl's children's stories to be released in his lifetime, it tells the tale of Mr Hoppy and his love for his neighbour, Mrs Silver, who lived in the apartment below him and keeps a small tortoise called Alfie on her balcony.
But the idea for this lovely story actually came to Roald Dahl several years earlier - as this extract shows.
In 1978, Roald gave a speech to an American group from Wright University in Ohio. In it, he talks about visiting his daughter in her London flat and the sudden inspiration that came to him as he looked down from her balcony...
The full, un-crossed out text of this section reads:
My eldest daughter has a flat in London. It’s on the 3rd floor, and it has a balcony outside. Not long ago, I was standing on that balcony, leaning over the railings and looking down to the balcony on the floor below, where there lives an old lady called Mrs Shrimpton. Mrs Shrimpton keeps a pet tortoise. In the summer it stays in a box on her balcony. In winter it is taken indoors where it hibernates for 5 months. (Over here, by the way, we don’t have pet turtles as you do, we have tortoises, brought in usually from North Africa or Greece. They are very long lived and very slow growing. I myself have had one for sixteen years now, and it’s still about the same size as when I got it.
So I stood leaning over the balcony staring at Mrs Shrimpton’s tortoise in its box below me. And quite automatically, almost subconsciously, my mind began to niggle around with a little story about that particular tortoise. It went like this.
I would go to a pet shop and I would buy eight more tortoises, the first one just a tiny bit bigger than the one I was looking at. The other seven would again be progressively larger and larger, but only a tiny bit each time. So that the last one was about twice as big as Mrs Shrimpton’s I would keep all eight of them in a box on my daughter’s balcony and feed them on lettuce – which is what tortoises like.
Then I would construct a simple grapple on the end of piece of string, so that when Mrs Shrimpton was out shopping I could lift her tortoise up out of its box and exchange it for one of mine.
First I would exchange it for the one that was only a very tiny bit larger than hers – not enough for her to notice the difference. I would leave that one there for one week. Then, I would get out my grapple again and exchange that one for another that was slightly larger still.
I would repeat this weekly routine for eight weeks – so that her tortoise was growing and growing – but because each change was so slight, she would not notice it.
At the end of it all, I would be leaning over the balcony, and I would say, “Have you got a new tortoise, Mrs Shrimpton?”
“No,” she would say, “I still have my beloved Bernard. I’ve had him twenty years now.”
“But he seems to have grown a bit hasn’t he?” I would say.
Mrs Shrimpton would look at her tortoise. “Now you come to mention it, he does seem to be a bit bigger doesn’t he? Let me weigh him again. I always weigh him at the beginning of each summer, when he wakes up. But he never changes much. A few ounces a year, that’s all.”
She carried the tortoise in to her kitchen scales. I waited on the balcony above. Then there was a shriek from below. Mrs Shrimpton came running out. “He’s doubled!” She cried. “He’s doubled in two months! He was exactly 4lbs in April and now he’s over eight!”
“How fantastic,” I said. “You have a magic tortoise.”
“I must write to the papers,” Mrs Shrimpton would say, jumping about with excitement. And she did. Soon her flat was invaded by the press, and photographs of Bernard, the fantastic tortoise,appeared in all the papers.
Then once again, I would get out my grapple, and slowly over the next eight weeks, I would set about reversing the process, until at the end of it all Bernard had shrunk back to his original size.
“How’s Bernard today?” I would say, leaning over the balcony.
“Oh he’s just fine, just fine,” she would answer.
“I can’t see very well from up here,” I would say, “but he doesn’t appear to be quite so big as he used to be.
Mrs Shrimpton weighed him again.
Another shriek of amazement.
“He’s shrunk!” she cried and so on and so on.
What is interesting about writing is that, unlike painting or composing music, one nearly always comes to it latish in life, usually in the late twenties or thirties.
Now the only point in telling you this little story is to try to illustrate how the mind of a writer of fantasy works. It is eager all the time to embrace what is absurd and far-fetched and above all what is comic."
The BBC One film adaptation of Esio Trot starring Judi Dench and Dustin Hoffman will be shown at 6.30pm on New Year's Day.