As the first signs of autumn began to appear last week I went horseriding with my sister in Trent Park, just north of London. It's mostly woodland, and for a lot of the time you can go without hearing or seeing another person, or car or any sign of modernity, even though it’s only a couple of miles from the M25. When you’re alone you can ride as fast as you like, which is to say as fast as you can, feeling the earth kicked up behind you, the forest a blur, the burn of little branches whipping you in the face. The horses we ride are only stable cobs, but the fantasy horse is always an Arabian.