We are all, Esme decides, just vessels through which identities pass: we are lent features, gestures, habits, then we hand them on. Nothing is our own. We begin in the world as anagrams of our antecedents.

Gretta sits herself down at the table. Robert has arranged everything she needs: a plate, a knife, a bowl with a spoon, a pat of butter, a jar of jam. It is in such small acts of kindness that people know they are loved.

She wanted to say, no. She wanted to say, I have a son, there is a child, this cannot happen. Because you know that no one will ever love them like you do. You know that no one will look after them like you do. You know that it's an impossibility, it's unthinkable that you could be taken away, that you will have to leave them behind.

As other authors have realized, heat can have a strange effect on us, can cause odd chemical reactions in the brain. Heat can bring out secrets; it can change people's personalities.

I was interested in the ripples of feminism passing through Britain and Ireland in the mid-Seventies - how the reverberations of the feminist political movement were being felt in suburban households. So many novels end with a marriage.

Why isn't life better designed so it warns you when terrible things are about to happen?

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.