What’s the first thing you see when you wake up? The huge pile of unread books by my bed. I buy too many books, then publishers and authors send more, probably 300 books a year. I can read 70 or 80 at the most.

Breakfast? Breakfast is at the flat, porridge and berries. I’m not much of a chef. There’s only breakfast in bed for my wife on Christmas and birthdays. But I do go and fetch the coffee.

Exercise? I run every Sunday with a couple of friends. We’re all in our 50s, and not as fit as we used to be, but we do between 5k and 10k before another coffee, sometimes through a park, sometimes by the river. We always end up at the same place: Sprio, on St Stephen Street [Edinburgh], a wee family-run Italian café.

Are Sundays for work or pleasure? If I’m writing a book, Sunday is just another day. I’ll be writing seven days a week. It’s not always a day of rest. If I’m not working, Sundays are when the family gets together. When I was young, family was what Sundays were all about. Now, at 59, I still cling to that.

Worst Sunday habit? Worrying about Monday. When you’re a self-employed author, you’re only as good as your last book, and you’re always worried that when you sit down tomorrow and start writing it’ll be no good.

Favourite Sunday from your past? I spent a very memorable Sunday a few years ago in St Lucia. I was on holiday with my wife to escape the worst of the Scottish winter. The idea for a new book just sprung into my head. I’m not shitting you: In A House of Lies came to me on a hot January Sunday in St Lucia. I tried to make the trip tax deductible, but the taxman didn’t buy it.

Last thing you look at before bed? Sadly, Twitter. I’m a bit of a Twitter junkie. I’m online too much, mostly on Twitter. Before that it was eBay.

Ian Rankin’s latest book is In A House of Lies (Orion)