"You-oo-oo-ve lost thaaat lovin' feeeelin/ Now it's gone, gone, gone,/Whoa-whoa-woh!" belts out the busker in the long tunnel that connects the Central and Northern Lines of the London Underground at Bank Station. He's accompanied by a tinny boom-box that builds a Lego-sized version of Phil Spector's "wall of sound". I'm not saying he's a bad singer - because he's not a singer at all, more a shouter who strikes attitudes with the mike. It's strange because, in these quality-control-obsessed times, you now have to audition to torture people in this way. I try hard to imagine what such an untalent show would be like, but can't - unless, that is, the Simon Cowell equivalents of Transport for London were actively seeking crap musicians.

That might well be the case, I continue to hypothesise as I allow my jaundiced eye to scan the oncoming people stream: goofy and glassy, split-endy and bendy, tall and short and hopelessly fat, all of them click-clack-slapping the tiles with that mounting frenzy that heralds the evening rush hour. After all, a critical consideration for public transport planners has to be a concept used in the science of fluid dynamics, namely, laminar flow. In a restricted column - such as a pipe, or a tube - streams of liquid will move parallel to one another without disruption, but if there are checks or disruptions, eddies may form. A good busker, by encouraging rush-hour commuters to slow down, might create dangerous cross-currents.

Peak practice

During the off-peak period, a proficient up-tempo musician might be desirable, provoking dense knots of dunderheaded teenage language students and valetudinarian tourists to get a fucking move on. The complexities of scheduling good and bad buskers with different tempi utterly preoccupy me until I find myself in a people purée struggling to mush itself into a Morden-bound train. "Please allow the passengers off the train," crackles the PA system, and then: "Move right down inside the carriages." I've grown up pulsing through the teeming arteries of the urban circulatory system, happy to be just another corpuscle. Arguably, on public transport systems, big-city rush hours exemplify not the madness of the crowd, but its sanity. You get your head down and go with it; too much thought is a dangerous thing, because if you pause to consider your situation - hemmed in by the herd - you might well lose it altogether. Which I'm in danger of doing, because one train has come and gone, then a second, and still there's no let-up.

Worse still, as we snuggle up to one another in the pack, the clones around me begin to become dangerously individuated. The tall man in the camel-hair coat whose buttocks are grinding into my thigh, I mark him well by the brocade of lost hairs on his collar, and by the shaving nick on his blueing jaw. And that young woman whose elbow is tucked beneath my ribcage, well, her pinched brow and smudging beige lipstick suggest premature despair; I can see her an hour or so hence, shovelling down microwaved Lean Cuisine in front of a soap opera, tearful in a bathrobe she stole from a Comfort Inn.

Tubeway army

At last I manage to get on a train - or, rather, the three of us do, still welded together like conjoined triplets. It's such a tight fit, the driver has to open and shut the doors several times, and my neck is uncomfortably kinked to accommodate the leading edge. As is always the way, within feet of this 3D jigsaw of limbs there's ample space, because no matter how many times it is urged to do so, the crowd is too unthinking to move right down inside the carriage. Over there people are reading newspapers, while over here our forced intimacy compels us to brainlessness - if I look into Camel Hair or Lean Cuisine's eyes, I can detect no more self-awareness than you would in the eyes of heifer being prodded towards an abattoir.
But then they probably feel the same way about me - and as we jiggle and jounce our way through London Bridge, Borough and all points south, it impinges on me how wrong I was: oh yes, you can be blithe about the crowd's sanity so long as it's achieving laminar flow, but in this frozen turbulence there is nothing but mental derangement. My gargoyle face distends and twists, my mouth gapes and unbidden the words splurge:

"You-oo-oo-ve lost thaaat lovin' feeeelin, now it's gone, gone, gone, whoa-whoa-woh!"

Next week: Real Meals