You see? If all you remember in years to come is the 'gay wizard' joke, I've come out ahead of Baroness Mary Warnock. Achievable goals: the first step to self improvement.

Actually, I have wracked my mind and heart for what I ought to say to you today. I have asked myself what I wish I had known at my own graduation, and what important lessons I have learned in the 21 years that have expired between that day and this.

I have come up with two answers. On this wonderful day when we are gathered together to celebrate your academic success, I have decided to talk to you about the benefits of failure. And as you stand on the threshold of what is sometimes called 'real life', I want to extol the crucial importance of imagination.

These may seem quixotic or paradoxical choices, but please bear with me.

Looking back at the 21-year-old that I was at graduation, is a slightly uncomfortable experience for the 42-year-old that she has become. Half my lifetime ago, I was striking an uneasy balance between the ambition I had for myself, and what those closest to me expected of me. I was convinced that the only thing I wanted to do, ever, was to write novels.