All the time I was plowing through books on dyslexia, I found myself asking: what if, what if? What if you were a kid the 1950s with this condition, when there were no books on it, when there was no understanding of it. I remember kids in my class at school who just didn't seem to progress in their reading. There was no extra help. People just thought, "Oh, he or she isn't so bright, or they're obstinate."

I don't believe in fate. I don't believe in cushioning your insecurities with a system of belief that tells you 'Don't worry. This may be your life but you're not in control. There is something or someone looking out for you -- it's already organised.' It's all chance and choice, which is far more frightening.

I met a retired police detective. And he said to me that the interesting thing about heatwaves, from a police perspective, is that the number of people who just walk out of their lives when the weather gets unbearable is astronomic. He said the police prepare themselves for it - for a huge rise in the instances of missing persons. People choose to disappear when it's hot. It was fascinating.

As you'll know yourself, there are these moments when you're writing a book when one remark or moment will pull everything together and you'll think, "That's it. I've got what I need."

When my family moved from Ireland in the 70s, Britain was such a difficult place to be Irish. It was a decade of real social and economic upheaval in Britain. There were strikes, the three-day week, the oil crises, huge inflation, the winter of discontent and, what was it, four Prime Ministers? And relations between Britain and Ireland at that time were at an all-time low. I was born in the year of Bloody Sunday and of course the pub bombings happened in the mid-1970s.

While I was writing the book, one of my children was diagnosed with dyslexia. Dyslexia is a very tiny word for a wide-ranging neurological condition that affects different people in different ways. But I was reading an awful lot about it, to try and find ways of helping my child. I think a lot of fiction comes from this desire to confront unanswerable questions, and it's heartbreaking to see your child, a bright child, struggling so much with something that others are finding so easy. It's such an assault to the child's self-esteem and, as a mother, it's hard to watch.

I think all families have these secrets, and it's sometimes the strangest things that bring them out. That was part of my interest in the heatwave, in heat as a catalyst for uncovering truths. I was reading Alice in Wonderland to one of my kids recently, and I remembered that it starts on a really hot day. Alice falls asleep because of the heat; the whole story is predicated on falling into a heat-fueled dream.