Jane Jesmond on what she likes best about writing.

What bits do I love writing most? It's a question that crops up from time to time and it's pretty tricky to answer because I love everything about writing crime fiction: plotting the twists and turns; inventing perilous situations for my characters to escape from; exploring interesting places for settings. Or at least I love it when the words are flowing!

But if you put a gun to my head and told me I had to choose, I would say that it's writing the characters and their relationships with each other that I get the most pleasure from. There's nothing to beat that moment when I suddenly feel I know a character better than my friends and family. When I know what they'll say or do or react without having to think too much about it. 

I've always thought that moment arrives because I put a lot of background work into developing characters - coming up with life histories, asking them questions and searching for pictures that convey some aspect of them - all to ensure that their actions and reactions are true to themselves or making sure there's a consistency running through them.

So I was a bit disconcerted when an interviewer asked me the following about Phiney, the often-grumpy nurse whose grandad dies in mysterious circumstances at the start of my latest book A Quiet Contagion. 

Tell me about Phiney, the interviewer said, she's a bundle of contradictions isn't she? And she went on to list all the inconsistencies in Phiney's character. 

After I'd spent the obligatory 10 minutes panicking that I'd got it all wrong, I made myself think a bit more calmly. It is true Phiney is contradictory and conflicted. She obsesses about living a chemical-free life while administering toxic drugs as an oncology nurse. She is judgmental (internally anyway) about other people while giving in to her own worst failings. But aren't we all contradictory? Isn't that what makes Phiney so human? So relatable? 

There's often a conflict between what we'd like to do and what we actually do. We behave differently according to the situation we find ourselves in. I have 100 times more patience in a professional situation than I do with my family. And while we're thinking about family, how many parents have been pleasantly surprised when an acquaintance has described their sulky, stroppy teenager as charming or considerate?

Maybe I had got it right after all! The development work, the histories, the interviews and pictures were part of the process leading up to the point where I'd immersed myself in Phiney's character enough for instinct to take over. Because so much of writing is instinctive - or at least it is for me. I do the background work. I plan. I produce spread sheets and use post it notes. I write brain maps. But, in the end, it comes down to the words that come out of my head and appear on the page as I'm writing and I often don't quite know where they come from. 

The Quiet Contagion by Jane Jesmond. (Verve Books) Out Now

Six decades. Seven people. One unspeakable secret. 1957. A catastrophe occurs at the pharmaceutical lab in Coventry where sixteen-year-old Wilf is working for the summer. A catastrophe that needs to be covered up at all costs. 2017. Phiney is shocked by the death of her grandfather, Wilf, who has jumped from a railway bridge at a Coventry station. Journalist Mat Torrington is the only witness. Left with a swarm of unanswered questions, Phiney, Mat and Wilf's wife, Dora, begin their own enquiries into Wilf's death. It is soon clear that these two events, sixty years apart, are connected - and that Wilf is not the only casualty. But what is the link? And can they find out before any more lives are lost?

Jane Jesmond writes crime, thriller and mystery fiction. Her debut novel, On The Edge – the first in a series featuring dynamic, daredevil protagonist Jen Shaw – was a Sunday Times Best Crime Fiction of the Month pick. The sequel, Cut Adrift, was selected as a Times Thriller of the Month and a Sunday Times Book of the Year upon its publication. Jesmond also recently published Her, a speculative standalone novel, with Storm Publishers. A Quiet Contagion is a brand-new standalone and her third book with VERVE Books.