You need a great idea, but then you've got to carry it through. If you get it right, you're going to be a critical success. But not everyone who works hard gets it right, or has the success they deserve: there's an element of luck.

The most difficult part of any crime novel is the plotting. It all begins simply enough, but soon you're dealing with a multitude of linked characters, strands, themes and red herrings - and you need to try to control these unruly elements and weave them into a pattern.

I don't have many friends. It's not because I'm a misanthrope. It's because I'm reserved. I'm self-contained. I get all my adventures in my head when I'm writing my books.

War created bizarre allies, while peace itself could be divisive.

I'm interested in Scotland now and then, how it's changed. I want to get the reader to think about that by thinking about something from the past. How has society changed, how has policing changed, have we changed philosophically, psychologically, culturally, spiritually?

I took the first James Kelman novel, 'The Bus Conductor Hines', home to my dad. I thought, 'My dad will like this; it's written in Scots.' But my dad said: 'I can't read that.' He was reading James Bond and John le Carre. That was part of what attracted me to crime - the idea of getting a wide audience.

A lot of writers, especially crime writers, have an image that we think we're trying to keep up with. You've got to be seen as dark and slightly dangerous. But I'm not like that and I've realised that I don't need to put that on. People will buy the books whether they see a photo of you dressed in black or not.