Book 3, another timeslip novel, has reached the crucial point where the historical and the contemporary stories have to be tied together and this is a tricky stage.

With My Mother’s Shadow, I wrote Addie’s contemporary strand first. Looking it over, I realised that I didn’t know enough about her mother Liz to really understand what made her do the things she did. So I wrote Liz’s diary. It was just for myself, to get inside her head, and only later did it become an actual part of the narrative. With Summer of Secrets, I turned it upside down and wrote the historical story first. During the last golden days before the outbreak of WW II, a country-house weekend goes horribly wrong and the heroine, Maddy Hamilton, is forced to grow up fast. I then wrote a framework around it: Chloe, a young photographer, is confronted with an unignorable crack in the facade of her seemingly perfect life when she discovers she is pregnant. Themes, emotions and tragedies echo back and forth across the decades as Maddy and Chloe meet at beautiful Summerhill, a country estate on the Cornish coast, and there find the strength to embark on a path of change.

Writing a novel like this — we call this genre ‘timeslip’ because you slip back and forth between time periods — is a bit like playing chess. You have to plan moves across the board and anticipate developments and snags ahead of time. You have to know past, present and future all at the same time. You have to know how something you do nowwill connect ten chapters later with something you didn’t even know then would exist. Yes, I know, it kind of does your head in even imagining it, and it’s usually at this point that I really, really wish I was better at chess.

I keep hoping a formula for this will magically appear. Connect A, line up with B, hark back to C. Sadly, timeslip plots don’t quite work like that and characters from two different time periods are even less cooperative, and you just have to keep track of all the moving pieces as best as you can. At the heart of Book 3 will be a devastating tragedy during the London Blitz, when London was bombed from the air for 76 consecutive nights. This moment in time will go on to shape the lives of the heroines for decades to come and will bring together past and present.

Me being me, I’ve made an excel grid, typed up several pages of fine print and have brainstormed across the better part of two notebooks. And, at the end of the day, I will most likely abandon all best-laid plans, sweep across the board and try to play my best game of narrative chess ever.