When a wolf doesn't want to do something, they look really cute.

My thirties merged into my forties, and I sort of gradually realised that I don't really want children. Now I'm glad I don't have them. Part of that is because I have my books.

My novel 'Wolf Brother' is set in northern Scandinavia during the late Stone Age, so I was aware from the start of Norse influences. I used some Norse names, and the soul-eater Thiazzi is based on the Norse storm giant, Thiassi.

At university - when I was supposed to be studying biochemistry - I had tried to write a children's book about a boy and a wolf cub, and there was a paragraph in that which was from the wolf's point of view.

I wanted to write a very simple story about a boy, a wolf, a girl, a bear and a forest, so I thought I might set it in the past. I didn't realise that it went back to when I was 10: I used to love the Stone Age when I was a kid and wanted to live in it, and I got rid of my bed and slept on the floor, but I didn't remember it.

Why do so many children love the idea of being snowed in or shipwrecked, of having to survive on one's own? When I was a child, I was no exception. I wanted to hunt with a bow and arrow like the Stone Age people: to skin deer and build my own shelter. And I desperately wanted a wolf. As we lived in London, my options were limited.