I burrow myself in the endless network of trains and underground tube for ever: when you cannot see whether it is day or night, it all feels like an eternity; when I re-emerge at Euston station, I am greeted by the usual pang of parcelled-up memories. There I stand among the confusing shops, half-hearted attempts at Christmas feel, confused people chasing after individual days.

I carry my takeaway fears and aches in a flimsy paper bag, ready to be spilled over by a coffee or a stripy jumper, the plastic flowers and the anodyne train announcements.

Elsewhere, I shall meet a friend whose face is less known to me than the soul. Together we endure the thousand stares at the National Portrait Gallery and marvel at the private lens of Annie Leibovitz. Eyes follow us everywhere. I have the feeling that, far from being the visitor, I am indeed the one who is been scrutinised and watched: Leibovitz looked for the essence of those she photographed, and it is that live essence which reverts the liaison between the public and the exhibit: I am examined by nude portraits and feel more naked than they are.

Our day is dotted with coffees and arguments about Mrs Thatcher; visual vs aural; and the unsustainable legacy of one's past.

If I could slice a portion of London and take it with me for later consumption, I would. As it is, I'll just have to go back for more.