The whole world and its leader are in town to make history. And not a little mischief

The omens for this week's summit extravaganza at the United Nations in New York, where more than 150 world leaders will be vying for attention between today and Friday, are not good. Last week, a dead crow, infected with the West Nile virus, was found at the front door of UN headquarters. On Monday, a chunk of ceiling fell into a hall where this morning the delegates will have breakfast.

The omens for this week's summit extravaganza at the United Nations in New York, where more than 150 world leaders will be vying for attention between today and Friday, are not good. Last week, a dead crow, infected with the West Nile virus, was found at the front door of UN headquarters. On Monday, a chunk of ceiling fell into a hall where this morning the delegates will have breakfast.

Responses to both events were swift. Acknowledging that West Nile is especially dangerous for the old and infirm, the Mayor of New York, Rudolph Giuliani, promised to have the entire neighbourhood sprayed with pesticide before the heads of state and government got in.

Last night, workmen painted over the hole high above the delegates' lounge. There is worry that the rain-sodden roof may drop more of its plaster. It is a concern, but Russia's President, Vladimir Putin, cannot be expected to eat his croissant while wearing a hard hat.

There is, you begin to surmise, high anxiety ahead of this meeting, described by the UN as the largest gathering of political leaders - including presidents, prime ministers, potentates and crown princes - our planet has seen.

And it is not the agenda of the summit itself that is giving UN officials sleepless nights. There are greater diplomatic challenges on this earth than agreeing a text on the need to eradicate poverty and reverse the spread of Aids. The worry is about all those things that might go wrong.

The potential for disaster cannot be exaggerated. Mostly, it is about security and protocol. How to do you avoid the United States President Bill Clinton and Cuba's President Fidel Castro being in the same room at the same time? How do you protect all these important people from terrorists and would-be assassins, especially when they will spend much of the three days in motorcades around town? And how do you do all this without bringing one of the world's busiest, and least patient, cities grinding to a halt?

Protocol has already claimed one victim. So angered was the delegation from North Korea, which included the country's number two, Kim Yong Nam, after members were allegedly ordered to submit to a strip search at Frankfurt Airport on their way to New York yesterday, that they turned on their heels and went back home. An advertised mini-summit between the Koreas in New York is cancelled.

At least that is one event fewer for the officials at the UN and the hordes of journalists here to contend with. As ever, it is not so much the summit that will be getting attention, or even the smaller round-table meetings into which the summit will be broken tomorrow.

The important stuff will happen in discreet bilateral meetings between government heads arranged on the summit's fringes. Tony Blair, for instance, has tête-à -têtes arranged with several of his peers, including Mr Putin. Britain has a small meeting room, assigned to the United Kingdom as one of the Permanent Five of the Security Council, on the third floor of the UN tower.

Other countries are not so lucky. With 700 of these face-to-face chats expected, little cubicles - also called "love corners" - have been arranged throughout the summit area. Some leaders will try to do their bilateral business in their hotels. The Waldorf, for example, will be the site for an expected three days of shuttling by Mr Clinton between the Israeli President, Ehud Barak, and the Palestinian leader, Yasser Arafat, in the quest for a Middle East peace deal.

Protecting against bruised egos is another conundrum. Each leader, however important, has been given a maximum of five minutes at the summit podium. One among them, President Hugo Chavez of Venezuela, has already served notice that he intends speaking for 30 minutes, come what may. And there will be no Oscar orchestra to silence him. Who knows whether Mr Castro will be able to respect the time limit? It was decreed long ago that all heads of state and royalty should be allowed to the podium first, with prime ministers to follow after. By the luck of the draw - indeed, lots were drawn - Mr Blair managed to get one of the last slots this morning, considered to be the prime-time of the whole three days.

For several days, the security net has been descending on the East Side of Manhattan. New Yorkers are beginning to feel it. The gridlock from this morning will be fantastic. Large stretches of the city's busiest avenues, including sections of Fifth Avenue and Park Avenue, will be closed to traffic. Nearer the UN, even pedestrians will be turned away from several streets. Looking down on the frazzled commuters will be a near-army of undercover policemen, roof-top sharp- shooters and secret service agents drafted in to stop attempted assassinations.

The freeze zones even extends to the East River, over which the UN looks, and to the FDR Drive, which runs most of the length of the East Side of Manhattan. The FDR will be closed from time to time whenever summit leaders enter some rooms in parts of the UN building that hang over the road.

There is also a risk of New York getting smelly, because the normal traffic of garbage barges from depots uptown down the East River towards landfills to the south will have to be partially suspended. The security officers feel hiding a missile amongst the detritus of the metropolis would be all too easy.

None of this is likely to endear the UN to New Yorkers, as they come back to town after the Labor Day break and the summer holidays. So the UN has spent almost $1m (£685m) on posters around the city declaring the importance of what will happen at UN headquarters this week and airing public service announcements with a similar message on the main television channels narrated by Harry Belafonte.

"History will be made here," the posters insist. Some kind of Batman beam of light will also illuminate the sky from UN headquarters tonight to advertise the summit's existence to New Yorkers who may be unaware of what is happening.

Perhaps Mr Giuliani summed up New York's love-hate relationship with the UN, when he offered this observation last week about the leaders and their impending summit. "They'll get protected better than any place in the world," he said. "But, as far as I am concerned, some of them I think are despicable, horrible human beings." Welcome, in other words, to New York.