Blaine prepares to leave the greatest freak show in town

Eye witness - The illusionist's greatest trick has been to keep us all wondering right to the end

The crowds were bigger than ever for David Blaine's penultimate day. "Look," said a father to a son in a conversation repeated, with variations, a thousand times or more on the land beneath the suspended box, on the crowded banks of the river and among the many watching from Tower Bridge. "Can you see him? A man in a box." The child, aged nine or 10 looked up. "What's he doing?" "Well," said Dad, "he's in a box."

Nearby someone was selling T-shirts with the slogan "Man in a Box". "You can do 'Show and Tell' at school on Monday and say what you saw. It's history." "Yeah," said the son, thoughtfully. "But Dad, what is it?"

Good question, and one with almost as many answers as there were people underneath the box yesterday. The enclosure, fenced off after all those hurled eggs, was full. The surrounding paths were also crowded with people who waved and shrieked at "David", who was reclining on one arm up behind the smudged perspex. "He copied my wave," said a bright-looking teenage girl. "He likes me."

But after looking at the box, scrutinising the wires for trickery, and wondering if it really was you he was staring at, there was little to do but inspect the crowd and think about shuffling away.

A sign on a fence reminded everyone that being present meant they agreed to be filmed "for exploitation worldwide without time limit by any manner and means whatsoever". Maybe it was a freak show - roll up and see the bearded lady, the wolf boy, the man in a box - but maybe the freaks were those of us who came to stand and wonder without any idea what it was we were looking at.

There were reports of Blaine suffering breathing difficulties and palpitations yesterday, but it is difficult to feel much sympathy when nothing may be as it seems. He may be fooling everyone, with secret nourishment in his water supply, or he may not be in the box at all. He is, after all, an illusionist.

The revelation that the "British Blaine", Derren Brown, used blanks instead of actually risking shooting himself in the head during his controversial stunt earlier in the month was hardly a surprise at all. Brown fooled people. That's what illusionists do: they allow us to believe the unbelievable. We don't really want to know how they do it either, whatever we say. If Blaine does reveal this to have been one very long trick there will be a widespread sense of deflation. Did we really spend so many pub hours talking about a modern version of the disappearing lady.

Then again, David Blaine may actually have spent 43 days and nights in a box, consuming nothing but water. If it's true, he's not an illusionist any more, but a mystic, aiming for enlightenment through endurance like an Indian holy man. Or he is a wacko. We are told his enclosure is an exploration of the suffering endured by his mother, who died slowly and painfully of cancer, and whose photograph he has with him. Which is touching, and harrowing, when you think about it, but does not give us very much to look at. Certainly not when compared with the misadventures of his fellow magician Roy Horn, whose onstage dalliance with a white tiger recently resulted in him being dragged by the neck into the wings in front of a live Las Vegas audience. Now that would have been worth seeing (to some people; others would call it sickening). If Blaine had a tiger in there with him, the crowds really would be huge.

Boontawee Siengwong understands this. The 26-year-old Thai has just moved into a glass room in Pattaya with 1,000 centipedes and will attempt to stay there for 28 days with the creepy crawlies free to roam all over his body (and into it, no doubt, through ears and mouth as he sleeps). "I'm very excited to have people come and see me," he said. If successful he will achieve a world record to rival that of his girlfriend, who recently spent 32 days in a box with scorpions. What fun they must have at home.

Meanwhile in London there has been little to look at except an increasingly hairy man waving weakly from under a duvet. The lack of spectacle helps explain why people have felt compelled to create their own by throwing eggs and behaving badly. But then there is an ancient British tradition that when people are confronted with things they do not understand - such as witchcraft, or different-coloured skins - they come to shout abuse. At least nobody has tried to set a blaze under the box to burn him (at the crane rather than the stake). So far. These words are being written on Saturday night, and there are still more than 24 hours to go. It would never do to underestimate the creativity of the British public.

Sky One, which has been filming the whole thing, says a quarter of a million people will have seen Blaine for themselves by the time the box is lowered to the floor at 9.30pm today. "It will then be tilted to the side and David will come out of the box," said a spokesman. "He will then be put on a stretcher and taken to a private hospital."

So is Blaine for real or not? His greatest achievement is that we have got this far without knowing. And that despite a lack of bullets, tigers or centipedes; and despite ourselves, we still seem to care.