Just what is going on?

The man in the blue shirt has barely reached into his bag of fruit when the heavies are on top of him. As he resists, lemon in hand, a walkietalkie appears to collide sharply with his temple and blood is pouring down his face.

The two guards bundle him down the Thames walkway and leave him on the ground just outside Ken Livingstone's eggshaped City Hall.

Shocked and livid in equal measure, he gives his name as Geoffrey and is about to launch into a tirade of abuse when his mates suggest that it is time to scarper before the cops show up.

Moments later, Geoffrey has disappeared. It is 1.30am but the night is far from over at the increasingly ugly freak show that is London's latest tourist attraction.

Intruders are lurking in the gloom. Up in his half-lit box, the target does not stir.

It is now almost a fortnight since American magician-cum-showman David Blaine began Above The Below, his quest to endure 44 days and nights without food in a plastic cage suspended from a crane opposite the Tower of London. His only sustenance is water from a tube.

But what started out as a bold publicity stunt by the 30-year-old New Yorker is rapidly turning into an alarming reflection of something rather unpleasant lurking in the British psyche.

For it is no longer Blaine himself who commands the headlines but the malevolence of some of those who come to see him.

Over the past 14 days, total strangers have felt compelled to abuse him, pelt him with missiles, tease him with food, disrupt his sleep and even try to blind him.

Earlier this week, a man was arrested after invading the support tower, issuing threats and cutting off Blaine's water supply.

Would-be tormentors like the bloodied and indignant Geoffrey are now a nightly hazard. Their actions go way beyond trite explanations like 'good, old-fashioned eccentricity'. Yes, Blaine is a TV-driven exhibitionist. But these reactions belong to the age of stocks, pillories, bear pits and rotten tomatoes. Wouldn't a more 'British' reaction be to ignore him?

As I stand on Tower Bridge in the early hours, I try to fathom what has compelled three men to turn up in a red, Y-reg hatchback at 2am, find a parking place 200 yards away, calmly fire three eggs and a beer can (all of which miss) at a man sleeping in a box and then return to their car as if they have just been to the shops.

WHAT is all the more disturbing is that it appears to be a uniquely British reaction. 'I'm truly amazed by this abuse. David never gets this in the States,' says his friend, Ben, a London-based American who turns up regularly to give moral support from a deckchair beneath the box.

Blaine certainly endured none of this last year when he stood, unharnessed, on a tiny platform 90ft above a New York park for 35 hours. The response of the American public ranged from admiration to indifference, but never downright nastiness.

'I've never seen this before,' admits Blaine's girlfriend, model Manon von

Gerkan, 30, who was so incensed by one egg-thrower last week that, when the guards caught up with the man, she urged them to hold him down while she reciprocated with an egg herself.

An estimated 30,000 people - a decent Premiership crowd - have already made the effort to see a lethargic man do nothing much in a box. Staff at Tower Bridge Underground Station have even erected a sign giving directions to 'David Blaine' as well as to the Tower itself.

Of the crowds gathered beneath the crane, a handful could be described as devotees, waving banners and squawking the sort of 'We love you!' inanities usually

reserved for boybands and Tim Henman.

Francois Greeff, 44, a campaigner for the handicapped homeless, has taken to engaging Blaine in a game of chess using giant plastic pieces and hand signals to interpret the magician's moves (thus far, scores are even).

Most people just stand and gawp for a few minutes, waiting for a wave. And forget any attempts to credit this scene with some sort of artistic merit. In 24 hours at this spot, I hear only one recurring topic of conversation among the crowds - and it is lavatorial.

The greatest excitement occurs

every few hours when Blaine wraps a sheet around himself and proceeds to relieve himself through a funnel connected, via a long plastic tube, to a small beehive contraption on the ground from where a bored-looking woman in blue washing-up gloves retrieves the results for medical analysis.

Talk then, inevitably, turns to more complicated bodily functions but no one is likely to witness one of those. (For the record, there have been just two, both in the dead of night and dropped, in bags, through a flap in the floor).

The daytime abuse is light. One magazine has taunted him with a hamburger suspended beneath a model helicopter. A Sunday tabloid tried to tease him with a barbecue.

'How's yer vitamins, David? Three million quid a day can't be bad,' yells an unsteady man in a tracksuit called Thomas who spends the day drinking cans of beer beneath a tree, emerging occasionally to tell everyone that Blaine is receiving secret vitamins and millions of pounds on a daily basis from the TV industry.

'Yeah, I saw him with some chicken McNuggets,' vouches another semi-coherent conspiracy theorist. 'He's not really in there at all,' a third assures me.

'This place really is a nutter magnet,' sighs a weary photographerassigned to the Blaine circus from the outset.

A spokesman for satellite TV channel Sky One, which has a 24-hour link to Blaine's box, ridicules any talk of millions and points out that his water supply is not only water, it is pure water (and thus devoid of the additives and minerals found in tap and bottled water).

But sunlit scepticism is the least of Blaine's problems. The mood darkens with the London sky. With night come the eggs - or worse.

It is 8.30pm and Yuri Geller, erstwhile psychic spoon-bender, has arrived with friends, as he does most nights, to lend support to his starving chum and voice his contempt for the attackers. 'I am very upset by all this hostility,' he says. 'David is strong and he will learn to endure it, but what really shocked me was a guy shining a high-powered laser beam into David's eyes. If that hit his retina, he would be blinded.'

GELLER'S party includes Lord Janner, the former Labour MP and himself a member of the Magic Circle. What does he think of Blaine's tormentors? 'They should be as ashamed of themselves as we should be of them,' he replies.

Suddenly Lynn Staff, 41, from Great Yarmouth, manages to slip through the outer security fence and is heading for the inner fence around the crane - minus her jeans.

Her pants are descending as the guards catch up and start heaving her back to the protective arms of her husband, Mark, who accuses them of stealing her jeans.

As I try to talk to the semi-clad mother-of-two, another bunch of oddballs intervene. 'I'm her agent and any talk comes through me,' screams a self-important young man who has appeared from nowhere.

Mrs Staff, who has never seen the man before, seems as baffled as I am. 'Actually, I came here because my husband and I wanted to make love in front of David Blaine but my husband chickened out, so I just went it alone,' Mrs Staff explains.

Blimey. This place grows weirder by the minute.

As I turn to leave, another man scrambles over the outer fence, straight into the arms of more guards.

They bundle him out of sight to a car park at the rear from where I hear screams until a flashing blue light heralds the arrival of the police.

Through it all, Blaine snoozes on. He may be a symbol of shameless exhibitionism. But so, too, is his barmy British audience.