One morning in 2018, my husband Reuben told me about a nightmare he’d had the previous night. He’d been driving over the Hewitt Avenue Trestle, a bridge near our house in Everett, Washington in the US, crashed through the barriers into the estuary below, and had to decide which of our two children to save.

Two weeks later, I was getting Talia, then three, and Weston, 10 months, dressed, fed and out of the door to take them to preschool on my way to work.

It was a route we’d taken a hundred times before. I was chatting to Reuben on speakerphone with both children in the back, when I smelled something odd,