Before I had kids I used to get up early to write. If I started at 6 or 7am, and was writing well, I would finish by 1pm, sometimes earlier. I can't do that any more because my eight-year-old son is a light sleeper like me and uses the excuse to get up and come in for a chat. I've told the kids they can come in whenever they want, and because they know this they don't actually bother that much. I've read of writers who enforce something like a prison "silent system" on their families, but there are more important things than writing.
The state of my desk is always an indication of how the writing is going. If it's tidy, I'm avoiding work. If there's clutter, it's going well and there's neither time nor inclination to clear up. I'm nearing the end of a series of eight short dramas for the BBC to mark the fifth anniversary of the invasion of Iraq. The process has been fast, for drama, about four months from commission to transmission (in March). I like it that way: working hard against a deadline, part of a team. But I also like it the other way: working gently, alone.
For distraction there's the radio and the iPod, and also chess, which I've played since I was a child. Zugzwang was inspired by the great Polish player Akiba Rubinstein. I co-write a weekly Guardian chess column with Daniel King and I usually set out the position we're examining on the chess table (by the furniture maker Tim Moss). The painting above the table is by the American artist John Fitzmaurice. I love the sensuality of his work, and the colours in this particular painting.
Above my desk there's a small collection of late-18th- and 19th- century chess sets. Some of them have associations because I bought them at around the time a novel was published or a friend told me she had cancer or a child started school, and so when I look up at them my thoughts will start to drift. Drifting thoughts are important to writers.