Where did the idea for Heroes of the Valley come from?
I’ve always enjoyed the Icelandic sagas, which were written in the Middle Ages. I manage to combine lots of realistic details about daily life and the actual history of the time with sudden incursions of the supernatural. The heroes of the sagas spend most of their time arguing about land boundaries and marriage arrangements and things, then go off into the hills to scrap with trolls and ghosts. The mix of fantasy and realism appealed to me, and I’ve attempted something similar in this book. Also, it was nice to try something rural and human-centred, after the djinni-filled London of the Bartimaeus books.

Who’s your favourite character in Heroes of the Valley?
I’ve two favourites here. Halli Sveinsson, the main character, is great because he’d love to be a swashbuckling hero, but is a bit stymied by the fact that he’s actually short and squat, with a face like a toad peering out in a rainstorm. And I love Aud Ulfar’s-daughter as well: she’s brave, kind and plain-speaking, and the only person in the whole valley who’s more than a match for Halli.