In old age, you realise that while you're divided from your youth by decades, you can close your eyes and summon it at will. As a writer it puts one at a distinct advantage.

The present hardly exists, after all-it becomes the past even as it happens. A tricky medium, time - and central to the concerns of fiction.

The idea that memory is linear is nonsense. What we have in our heads is a collection of frames. As to time itself-can it be linear when all these snatches of other presents exist at once in your mind? A very elusive and tricky concept, time.

We open our mouths and out flow words whose ancestries we do not even know. We are walking lexicons. In a single sentence of idle chatter we preserve Latin, Anglo-Saxon, Norse: we carry a museum inside our heads, each day we commemorate peoples of whom we have never heard.

But who knows their own child? You know bits - certain predictable reactions, a handful of familiar qualities. The rest is impenetrable. And quite right too. You give birth to them. You do not design them.

Grief-stricken. Stricken is right; it is as though you had been felled. Knocked to the ground; pitched out of life and into something else.

I do like to embed a fictional character firmly in an occupation.