One hot summer’s day, my uncle took my older brother and me fishing on a river in Sussex. The river was so polluted with hormones, my uncle said, that the fish were constantly changing sex, and if we ate them we’d grow breasts. We used balls of cheese for bait, our plastic floats bobbing in the beef-stock brown water as we slapped at horseflies.

My brother and I had been thrown together when I was three and he was seven. He was my adoptive father’s son from a previous marriage. So he was the rightful chick; I was the cuckoo’s egg. There was a lot of jostling in that nest.

We cast and recast, catching nothing but weeds. It was a competition, though I hadn’t realised that yet. Everything was a competition to my brother. His float twitched, and he reeled it in. First catch of the day. A muddy little fish jumped out the water on the end of his line and writhed pathetically in the air.

‘Aw, it’s just a little tiddler,’ my uncle said. ‘Better throw it back.’

‘Just a little tiddler,’ I repeated, sing-song style.

I was up and running before my brother had thrown his rod down on the bank. Bare feet through the long grass, blades catching between my toes, squealing like a piglet. He came at me like an angry white snake, tangled my legs, and pressed down on my chest.