Spending a lot of time away from home was strange. My parents visited me, obviously, but I was in hospital a lot, alone. And then when my health had improved a bit and I was in a sick-bed in the house, with the life of the house going on around me, that was very vivid for me. I always think that's a bit like the position of a novelist in a novel, going through drafts: there but not there, one remove from reality.

In the course of writing a book I'll produce loads of pieces of paper to help the novel itself. Diagrams, charts, family trees. And at the end of each book I'll pack it all away. It takes me a while to do it - it's like a relationship that way; there's a period of letting - go, of grief, in a way - but then I box it up, label it, and put it in the attic.

I still have a stammer. I hate it; I loathe and despise it. But it's always there, and I have lots of ways to conceal it. I can conceal it now but I'm not good on the telephone. I get my husband to make dentist appointments. And I hate live radio. Hate it. I really try to avoid it at all costs. But it's always there. Stammerers become skilled at sentence construction and synonyms: we have to be. Faced with a problem word, we need to have instant access to eight others we could use instead - ones we could say without stumbling. I think my stammer is a huge part of my being a writer.

I always had the urge to write. Not in the sense of wanting to be a writer, but just writing things down, getting words on a page. Graphomania, it's called. I've always had a definite love of stationary products - I used to spend all my pocket-money on pens and notepads. I still do, in a way.

When I worked at The Independent newspaper, I had colleagues who would laugh and say that whenever they picked up the phone to my dad and heard his accent, they thought they were about to hear a five-minute warning to get out the building. People in Britain have always thought it acceptable to make racist remarks about the Irish. The prejudice underlying that supposed joke was everywhere.

I have two sisters, and I think siblings are always going to be irresistible for novelists. They have been throughout time and they'll continue to be.

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.