Ten years ago I was trying to write a contemporary novel set it in London, where I’ve lived all my adult life. But something was holding me back. I kept finding myself diverted back to my childhood, and in particular to a haunting if somewhat run-down stately home on the North York Moors where I spent my formative years, aged 8-12, at a boarding school. But I was very resistant to converting my 1970s school experiences into a novel; that would have felt too direct and personal.

Yet all that changed when I was making a documentary about the novelist Elizabeth Bowen, and watched some footage of two nervous evacuees smiling for the camera on a London station platform in 1939. I remember feeling an instant pang about these small children leaving their parents behind – perhaps partly because I had two daughters exactly that age, but also because I remembered the ache of leaving my own home behind at eight. There was an extra resonance for me because I knew that my mother had been evacuated as a wartime child, and that the trauma of that separation from her parents had been a factor, strangely, in sending her own children away from home at a young age.

Not long after that, I visited a glorious stately home in Cornwall called Llanhydrock, where they have devoted a special archive to the evacuees who lived there during the war. Again, I found myself gripped by the photographs of these displaced children with their brave smiles. It struck me then that there was a way of writing about the hauntingly beautiful Yorkshire house which had dominated my childhood, but setting it during World War Two. Ashton Park began to form in my mind as a place in which a series of elective affinities play out during wartime, as witnessed by a visiting evacuee.

An evacuee is the quintessential displaced or lost child – I think that was why Anna Sands lodged herself in my mind. If ever there were children at crossroads, it was evacuees, who set off on their trains to unknown destinations, and found their lives changed forever by the new families they joined. The emotional consequences still trickle down the years.