You might not expect Jones to be nervous about the publication of her third novel, The Uninvited Guests, given the critical and popular acclaim heaped on her previous books, but still she feels "exposed".
"I'm never happy with what I've written," she says. "You imagine, before you start, there's a cathedral, and the moment it starts on the page, it's a garden shed. And then you just try to make it the best shed you can."
This is not false modesty, but it should be. Jones's debut, The Outcast, a vivid tale of emotional repression in 1950s England, won the Costa award in 2008 and saw her writing compared to Ian McEwan and Kazuo Ishiguro. Her second , Small Wars, was an examination of a marriage in 1950s Cyprus and, according to one critic, "one of the best books about the English at war ever".
Success came as a shock to Jones, who had spent 15 years as a screenwriter, trying – and failing – to get her work produced. "Life is not a meritocracy," she says now. When The Outcast was published, she was 40 and a mother of two – Tabitha, now 15, and Freddie, 13 (she is married to the architect Tim Boyd). The reception was "ridiculous. Like being bombarded with sweeties…When you're in it, you think the whole world is looking at you and you're basically Geri Halliwell."
With The Uninvited Guests Jones has abandoned the 1950s in favour of a fizzing supernatural tale set over the course of one night in an Edwardian country house. Comparisons to Downton Abbey are inevitable – although Jones started work on The Uninvited Guests in 2009, a good year before Lady Mary put in her first appearance on ITV.
"When it started I was some way into the book and I was terrified of watching it," she says. "Then I saw it and thought: 'Oh, that's all right, that's completely different.' It was an enormous relief."
She remains an acute observer of detail: a legacy, perhaps, of her upbringing. Her father is the Jamaican poet Evan Jones and she recalls being the only girl at Godolphin & Latymer school in London who went to Jamaica for the holidays. "I remember people saying: 'You look funny, your hair is so black, you have a flat nose,' but I didn't think of it being racism and I still don't. But there was a sense of difference, of being an outsider." Did that made her a better writer? She laughs: "Oh, I always think everyone feels left out."