Most of the people who write to me are really clever, really engaged. They just want to say that they have read my book and liked it.

There's always these giant baffling books, like 'The Da Vinci Code.' People say it's not as well written as 'Midnight's Children.' Why aren't people reading 'Midnight's Children?' Nobody knows why these phenomenons happen but they're great.

None of us know what is going to sell or what people want to read.

I respond very well to rules. If there are certain parameters it's much easier to do something really good. Especially when readers know what those are. They know what to expect and then you have to wrong-foot them. That is the trick of crime fiction. And readers come to crime and graphic novels wanting to be entertained, or disgusted.

I'd read so much right-wing crime fiction where they find the evidence and shoot the bad guy - I thought there must be another approach.

I just got an honorary degree from Glasgow University, and I had to wear around very painful shoes so that I didn't laugh all the way through the ceremony because I felt like an outlaw.

In the 'Garnethill' trilogy, people always forget that Maureen O'Donnell's dad was a journalist and she did art history at uni and her brother did law, but no-one ever thinks they're middle-class - they're just working class because they speak with accents.