‘The Norwegian Environment Agency. They have to check the threats posed to the river from alteration.’

‘Threats?’ Tom says, folding his arms. ‘What kind of threats?’

‘The river runs into the fjord; the fjord runs into the sea. The alteration might cause harmful substances to suddenly enter the ocean. We have big problems with sea lice in the fjords just now because of people like you. Wild salmon numbers falling. Genetic mixing. Big problem.’ Tom bristles at people like you. ‘Wildlife will use this river as their water supply,’ Ragnar continues, stepping to the other side of the river. ‘Wolves, bears, elk. They might be affected. One river we worked on had sixty-five different species using it on a daily basis. Sixty-five.’

‘I’ve not spotted anything using the river,’ Tom says, knowing as soon as he’s said it how petulant this sounds.

‘They’ll be using it at night,’ Ragnar says. ‘If you set up a night camera you’ll be surprised. Ecosystems are very sensitive to human interference.’

‘How long does it take to get a permit from the Environment Agency?’ Tom asks.

‘Very big backlog. Problems with overdevelopment, you see. Lots of people like you building houses just now. I’d say … six or seven months.’

Tom can’t conceal his dismay. He thanks Ragnar for his time, says he’ll be in touch. Lies. Even as the man is getting into his car he’s thinking of how to do the job himself. He hasn’t got six or seven months. And the river is hardly Niagara Falls.

He relays this news to Aurelia, who is disappointed. Such is the dejection in her face that he tells her not to worry. He’ll do it himself.

The next morning he pulls on his wellies, thermal gloves, and Gore-Tex jacket, and takes a spade, a flask of tea, and a wheelbarrow of concrete blocks to begin damming the river. It’s a mild, silvery morning, a white scarf of mist draped over the hills, the sun a splash of orange against mother-of-pearl sky. There are cataracted slabs of ice here and there, some of them several inches thick, but for the most part the river runs fresh and clean through the trough of pebbled earth carved out over millennia. The insistent movement of the river is startling, even touching, amongst so much stillness – the land’s vibrant pulse. No signs of any salmon, or fish of any kind. It’ll do no harm to divert it.