The National with knobs on Letter From Melbourne

Tomorrow at 3.20pm (4.20am GMT), Australians young and old will drop whatever they are doing (it is to be hoped that no open heart surgery is being performed) to watch 24 thoroughbreds gallop their socks off around a pear-shaped course in the western suburbs of Melbourne.

Tomorrow at 3.20pm (4.20am GMT), Australians young and old will drop whatever they are doing (it is to be hoped that no open heart surgery is being performed) to watch 24 thoroughbreds gallop their socks off around a pear-shaped course in the western suburbs of Melbourne.

It is no ordinary horse race that will bring the country to a halt for just over three minutes. It is the Melbourne Cup, the most eagerly anticipated event of the Australian sporting calendar. A crowd of 100,000 is expected at the Flemington course; another 15.5 million people (85 per cent of the population, babies included) will tune in via television or radio.

The Cup, held on the first Tuesday in November, is not just an occasion for an annual flutter, although wallets will be £42m lighter by the time the barriers go up. It is an excuse for a prolonged session of unbridled partying that is the high point of the year for a hedonistic nation. In the state of Victoria, Cup Day is a public holiday; elsewhere, precious little work is done, thanks to social gatherings ranging from swanky hotel Cup lunches to backyard barbecues.

The two-mile flat handicap is Australia's richest race, with £1.26m in prize money. This year the field is tantalisingly open, with five horses posted at single-figure odds following a string of last-minute upsets that included the relegation of the early favourite, Tie The Knot, to 7-1 after a disappointing run in the Mackinnon Stakes at Saturday's Victoria Derby.

Sky Heights, Australian winner of the recent Caulfield Cup, is the new favourite at 7-2; also strongly fancied, at 5-1, is another local, Rogan Josh, trained by the legendary Bart Cummings, the man behind 10 Melbourne Cup winners.

Hopes of a first British victory were dealt a blow when Kayf Tara, from Sheikh Mohammed's Godolphin stable, was scratched following a leg injury. Sheikh Mohammed, whose ambition is to dominate world racing, has substituted Central Park, Kayf Tara's stablemate, running at 33-1.

Central Park will be ridden by the Frankie Dettori, who has yet to win a race in Australia and complained a few days ago that most of the rides offered him Down Under have been "sausages". The best British prospect is now Travelmate, runner-up in the Northumberland Plate, quoted at 6-1, but there are two other outsiders: 25-1 Yavana's Pace and 100-1 Maridpour.

The Cup is the centrepiece of a four-day Melbourne Spring Carnival and, for party animals, the highlight of a week of festivities - a day when the public enclosures are knee-deep in beer cans and prone bodies have to be prised off the lawn.

Stuart Gregor, limbering up at the Derby on Saturday, said: "The great thing about coming to the races in Melbourne is that it's quite reasonable to be well pissed at 11am. Champagne is the drink of preference for the first few hours, then we move on to beer. We back the occasional horse too, although generally not after lunch."

At the classier end of the market, the place to be seen is the Birdcage Car Park where, in the finest traditions of Ascot and Cheltenham, massed ranks of Range Rovers disgorge picnic tables adorned with white damask and silverwear. Were it not for the nasal accents, you could be in the Home Counties. The men are in morning suits, the women sport outlandish headgear.

"Glorious, isn't it?" trilled Gilly Swinnerton, in Flemington for the day with husband Gerald. "Thank goodness it's stopped raining - absolutely fatal for suede shoes, don't you find?" The fashion stakes are high and the men are as ruthless in their sartorial judgements as the women.

"Mate, he's wearing a $25 suit made in Bali and white socks with shoes, I'm telling you," muttered one racegoer to his friend, indicating the hapless victim.

For guests nibbling on sushi and filet mignon in the silk-lined corporate hospitality tents, there is an added bonus this year: the racing. Companies such as Saab and Emirates have built elevated marquees overlooking the track for people who might otherwise depart without having seen an ounce of horseflesh.

But for most people, the equine entertainment counts for plenty. This is, after all, the country where Phar Lap, the 1930 Cup winner, is a national hero whose stuffed remains are paraded through the streets of Melbourne in a glass case on the eve of the big race.

The Melbourne Cup is a Grand National with knobs on, and then some. As Mark Twain wrote after attending the race in 1890: "Nowhere in my travels have I encountered a festival of the people that has such a magnificent appeal to the whole nation. The Cup astonishes me."