People had tell me the most personal things. People I'd never met before would say thing like "Oh, that was the summer I had an affair with my neighbor." The 1976 heatwave occupies a peculiar place in people's psyches.

For a while I used to listen to those whispers about babies costing you books, and Cyril Connolly's loathsome quote that "There is no more somber enemy of good art than the pram in the hall." But it's rubbish. Absolute rubbish. A huge amount of your work is done when you're not at your desk. Knotty problems that you need your unconscious to solve. So it can be helpful to walk away and focus on other things and it can be helpful to be a bit harassed in your daily life, to be hungry for time to write.

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.

My husband, William Sutcliffe, the writer, is my first reader and in many ways my most important. That initial reading of the manuscript is crucial and irreplaceable and you want them to approach it as someone in a bookshop might, not knowing much about it. So I've got into this pattern of not telling Will anything about the book I'm working on. He often knows nothing about the book I'm working on at all until I give him the whole manuscript and ask him to read it. The book I'm working on at the moment he knows nothing about. No one does.

The role you've been ascribed in childhood can twist or break apart or seem outgrown, especially when you have your own family and begin to see your own childhood from a different angle. You remember. You reassess. I think that was the kernel of the novel for me. This idea that you change but that your family, the people you were born into, might find that change hard to accept. You no longer fit the mold you've always been ascribed. When the adult children in the book converge back on their small family home there's a sense that they don't fit there anymore.

There was so much anti-Irish sentiment not just from other kids at the school I went to in Britain, but also the teachers themselves. I remember very clearly a lot of the things people said to me and my sisters. And of course those sentiments go back a long way. When my dad visited London in the 50s and was looking for somewhere to stay, there were signs outside boarding houses that said "No blacks, no Irish."

Listen. The trees in this story are stirring, trembling, readjusting themselves. A breeze is coming in gusts off the sea, and it is almost as if the trees know, in their restlessness, in their head-tossing impatience, that something is about to happen.