I state the obvious here, but it's always I think, worth repeating; major cities such as London, NYC, LA, Paris and every other megalopolis, are not worlds entire of themselves. World is too small a term, something far greater is required: they are individual galaxies, a confusion of whirling nebulae, of randomness and chaos, of ceaseless collisions of different and infinitely varied lifestyles.

It is this permanent state of happenstance, never quite knowing what's just around the corner, that makes London and it's sister cities, intoxicating. Why live anywhere else, when as in the instance of yesterday, within the compressed space of perhaps a mile, a friend and I stumbled into a Hare Krishna street festival hard by the northern fringe of Soho Square and into a tight funnel of ash-marked and finger cymbal clicking devotees

A scant half mile from that we wandered into St Martin's in the Field, which until Saturday I had never been and this is in spite of living in London for nearly thirty years, but that's the untold confession of so many Londoners, what we have n't seen but virtually everyone from out of town has. Something made very obvious for me the day I went on a fact-finding mission for an American script writer friend to the British Library, who wanted some background on the King's Library. I'd never heard of it until he mentioned it.

The King's Library, if you're interested is a beautiful six floor glass chimney of rare books and a commanding presence as you enter the British Library. How I had missed it on the umpteen occasions I've been to the BL is a mystery to me, other than referring back to the point I made a little earlier - you live here, but you don't see the obvious things. On the other hand, ask me where the best coffee shop, indie bookshop or humus bar is in London, then I'm your man.

There was a mixed Anglo-Chinese choir running through their pieces when we walked into St Martin's, stopping and starting at the baton swing of the choir master. Everything they sang sounded good to me, but clearly not good enough him. We sat on one the side pews, and through my film-goer's inner eye, it could have been a shot from a gangster movie, where the the two warring Dons sort out their temporal differences against a spiritual background of a choir rehearsing.

Finally, we washed up on the Southbank. An area of London that has been transformed since I first arrived here; for years a no-no area, the tumble weed blowing down the streets, bleakness of an abandoned gold rush town in the eighties to true bon-ton, arty middle-class, boutique bohemianism today.

Threading through long tables of second hand books for sale and the crowds wandering to and fro from the NFT, we bumped up literally into a group of free runners, backflipping and somersaulting by the the National Theatre. It looked exhilarating. The suppleness and daring of urban gymanstics, side flips, twists, turns on hard concrete surfaces. All of the free runners were unself-conscious. This was their area. Nothing else to consider but the easy agility of the next move.

And this is the thing about London: it's a city of parallel events which never meet in time or space, they exist on their own, self-contained; it's the casual strollers like my friend and I yesterday, who accidentally link it all together without ever thinking about it.