The new David Blaines

So this is how it feels to be a work of art. I stepped into a large glass box behind Nelson's Column that houses London's most peculiar event, Reading One Million Years by the Japanese conceptual artist On Kawara.

For seven days from 8am this morning, 24 hours a day, several pairs of men and women will sit in this box and read from two printed lists of years, from 998,031BC to AD1969 - the year the mysterious On Kawara conceived the idea - and AD1980 to AD1,001,980. My participatory moment came during the sound check yesterday.

"Ninety-thousand, eight-hundred and fifteen AD," said 31-year-old Joshua Sofaer, his careful diction floating out into Trafalgar Square. "Ninety-thousand, eight-hundred and sixteen AD," replied 46-year-old Marcia Farquhar, sitting beside him.

This public performance will be more continuous than previous gallery showings in New York, Kassel and Kwangju, but even working flat out the British team will only read out around 217,000 years.

My offer to reel off a couple of dates was politely rebuffed. That, it was explained, was like asking to have a go with Lucian Freud's paintbrush, or Damien Hirst's chainsaw. So I tried to look suitably solemn, as if I were contemplating the vastness of time.

On the other side of the glass, tourists looked mystified. Some were waiting for the box to rise into the air - the shadow of David Blaine and his glass box starvation stunt hangs over this venerable piece of conceptual art.

"This is nothing like what Blaine did," said an exasperated Margot Heller, director of the South London Gallery, which is producing One Million Years. "It's very moving, and I hope it will provoke a variety of responses, like all good works of art."

But everyone involved remembers how Blaine was flashed at and pelted with eggs. And this is Trafalgar Square, the focal point for homegoing clubbers as well as National

Gallery devotees. "There's no way I'd do the night shift readings," said Joshua Sofaer.

Fellow reader Claire Wright added: "The piece has quite a soothing rhythm, so I hope it will have a calming influence, even on people queuing for night buses. Anyway, the box is bullet-proof. Or so they tell us."

Most Londoners and tourists seemed glad to have it there. Devin Rousso, eight, on holiday from Los Angeles, said: "It's kinda boring to watch, but it might be cool to actually take part in it." It is, young man, it is.