Prescient, the Brazilians. Years ago, they agreed to be first at the podium at the UN General Assembly each September when nobody else was volunteering. Ever since, they have been allowed to keep the now highly prized slot, which always guarantees a full hall – the Americans come after.

Everything is jockeyed for at the General Assembly. The order of speakers is up for grabs months in advance and operates on a first come, first served basis – except that presidents, potentates and despots get priority over, well, mere deputy prime ministers. Nick Clegg had to settle for late this afternoon.

Embassies spend all year preparing. Will the food be to their leaders' liking? Will they get face time with Barack Obama or Hillary Clinton? For the UN Protocol Office there's the added task of ensuring that foes don't end up eating together or colliding in a lift. Were Obama and Iranian President Mahmoud Ahmadinejad to end up sharing bathroom facilities, disaster could ensue. (Or conceivably a toilet treaty.)

Also furiously pursued are spectator seats at the summit itself, particularly when the rock star leaders speak – Obama and Ahmadinejad among them. A little red ticket will get you in, if you can find one. The British mission seems to have cornered the market, it's handy to know.

"It's a logistical nightmare," Desmond Parker, the head of protocol, confessed this week. It hardly helps that most of the iconic UN tower has been emptied for renovation. The speeches still happen in the old General Assembly hall, its roof covered in white plastic because of leaks, but the side meetings have been moved to a temporary shed-like structure built on what used to be the UN lawn.

"You can imagine how difficult it is for us to accommodate people and move around and get things flowing the way they should flow," Parker noted. And that's just inside the UN campus. Try moving around in the city where the siren-and-lights caravans of 194 leaders paralyse every avenue.

So don't get lost, and don't be late. That man with a fan of greying hair charging down a walkway in the sun is late, for certain. Barack is about to address delegates about world poverty and Bob is within a squeak of missing it. Not a diplomat or an overseas aid minister, but an old rocker, Bob Geldof.

Had Bob turned right instead of left he could have opted instead for the Maternity Conference with Clegg and Hillary and Miranda. Melinda has more money than power, because her second name is Gates and her husband was yesterday named the world's richest man, again. Seats at the maternity event were even more scarce than seats in the main hall."You cannot please everyone," says Parker. And the choreographywas not quite perfect yesterday. President Inacio Lula da Silva of Brazil didn't show up at all. Mr Obama was late. Switzerland went second and America third.