The process of writing The Anniversary was quite messy and complex, and it started out a very different kind of book.

The early drafts told a straight story, with the events narrated in chronological order with the narrator telling us the story of her life. But there was something about this that made me feel slightly bored and didn’t quite convince: she told her story almost too easily, without reservation or correction. Some energy or trouble was missing. I realised that what I was really interested in was how we tell our life stories, which is so rarely consistent or chronological. We are so often unreliable narrators of our own experience.

The book helped me understand that one of the things I’m fascinated by is the way we give an account of our histories – how we filter or repeat the story of an experience, presenting it from one angle then another, qualifying, hedging, checking, revisiting, questioning, even when recounting these experiences to ourselves. The book gave me a way to really explore the complexity of this, especially in relation to women’s stories.

Writing a book is a deep form of obsession: for months I live through the filter of the book and every experience is coloured by an endless and distracted novelising.

It’s really important to me that my writing is character-led, but writing this book showed me that the very shape of the book, its form, the organisation of it parts, its timing, can also – in the deepest way – be determined by the consciousness of the character and determined by what the character wants to hide as much as by what they prepared to reveal.

About halfway through the writing process, I realised that I had pretty much no idea of where I was going – I think I knew one vague thing about how it all might end – and it came down to having to trust the voice of the narrator in quite a mysterious way. I wrote fast and I wrote a lot, just to get closer to a point of breakthrough.

Writing a book is a deep form of obsession: for months I live through the filter of the book and every experience is coloured by an endless and distracted novelising. It’s a kind of parallel universe that has an addictive pull. I thought I needed to know where I was heading with the book, but the more I wrote, the more I realised that so much of the pleasure of writing for me is about following a trail of not knowing, discovering the events with the same surprise that I want my readers to feel and then letting that energy feed into the writing.