There is no racing spectacle quite like the Grand National. You never forget the roar from the crowd as the tapes go up, the cavalry charge to the first fence, the field streaming past the Canal Turn, and jockeys beating their whips on the ground in frustration at the chance of glory gone for another year after failing to negotiate one of Aintree's hefty birch fences. And, finally, that lung-sucking, leg-sapping endless run-in from the final fence as the prize is determined.
Unlike the Cheltenham Gold Cup, the National is a handicap. Yet racegoers cherish the memory even of horses that were beaten in the National. They never forget the bold front-running Crisp, the top weight beaten by Red Rum in the greatest race ever in 1973, or the Queen Mother's Devon Loch, who spreadeagled on the flat just short of the winning post in 1956.
Ginger McCain, now 74, trained Red Rum to be first in three Nationals and second in two more. Last year he won again with Amberleigh House, and he says: "You can have your Gold Cups at Ascot with all those toffee-nosed people, you can have your Cheltenham with all your county-set types and tweeds, but this is the people's race."
He is right. Crowds stream over the course to pay homage to the daffodil-bedecked grave of Red Rum in the shadow of the winning post. As the spring-blossom petals swirl in the breeze, families line up for photographs with his bronze statue near the parade ring. Aintree on National Day has a magic.
Picking the winner of a handicap that sees 40 horses battle through 4½ miles over 30 fences requires a little magic too. But statistics aid the elimination process. No French-bred horse has won since 1909. No seven-year-old has won since 1940 and, although handicapper Phil Smith tries to give top-class horses a chance by lowering their weights compared with the burden they would carry over three miles of a park course, no horse has won carrying more than 11 stone since Jenny Pitman's Corbiere in 1983.
Winners usually come from the nine-11 age range (though Amberleigh House was 12) and from the top 10 in the betting. Almost invariably they have had a run within the past two months and have been proven over more than three miles.
And it seems there is an "Aintree type". Amberleigh House had run third a year before he won and had previously won the 2001 Becher Chase over the National fences. Clan Royal, second last year, won the Becher Chase in 2003. And Monty's Pass, fourth last year carrying a hefty 11st 10lb, won the National in 2003.
This year much attention has focused on Forest Gunner, a scrawny toast-rack of a horse trained by motorcyle enthusiast Richard Ford. Forest Gunner won the Foxhunters Chase at Aintree last April and then won over the big fences again last November in the Grand Sefton Chase. In February he collected the Red Square Vodka Gold Cup over Haydock's tough fences.
But it is the fact that Ford's wife Carrie will ride that has excited the media, especially because she was in the saddle for the horse's victory in the Foxhunters Chase just 10 weeks after having her first child. At that point she retired for baby Hannah's sake, but has come back for the big race.
The excitement intensified after McCain ungallantly dismissed her chance, proclaiming: "Carrie is a broodmare now and having kids doesn't get you fit to ride."
If Forest Gunner does win Ford will be the first female winning rider in the race's history. But if anybody can do it, she can. She has been champion female National Hunt jockey and won the ladies amateur title twice. She has only had three rides in public this season but has been making her thigh muscles burn during 20 miles a day of riding work for her husband as well as daily swimming and running. It would be a hugely popular success if she were to win.
Of the competition, Clan Royal would have to be feared in an ordinary year. But for his trainer Jonjo O'Neill this has been a nightmare season. His state of the art Cotswolds yard has had to be shut down for weeks with his horses suffering from a virus. They have been dribbling back to the racecourse lately, but only with limited success.
When O'Neill triumphed with Schapiro at Newbury on Saturday, I asked after Clan Royal, who has not seen a racecourse since last year's National. "He looks fine, like this fellow," said the trainer with a wry smile, indicating his winner. "I only hope he will run as well."
But it cannot be the ideal preparation for a 4½-mile stamina test and the bookmakers are not being generous with their 10/1.
At 13 years old, Amberleigh House seems unlikely to triumph again, and Hedgehunter is this year's favourite. The Irish carried all before them at Cheltenham this year and they have done well in the National in recent years, winning with Bobbyjo in 1999 and Papillon in 2000 as well as with Monty's Pass. Hedgehunter, trained by Willie Mullins, has finished out of the first four on only six of his 26 starts. But one of those six was last year's National when Hedgehunter crashed at the last fence looking a very tired horse.
Like Clan Royal's owner JP McManus, Hedgehunter's owner Trevor Hemmings has spent a fortune trying to find a National winner, so far without success, and I suspect that McManus's Spotthedifference, fifth in last year's race and a winner of the cross-country chase at the Cheltenham Festival, will prove the best of the Irish.
A bigger threat to Forest Gunner could be Strong Resolve, an 11/1 shot trained in Scotland by Lucinda Russell. Runner-up in the Welsh National at Chepstow, he jumps well and should relish the National trip.
And for a long shot at fancy odds, try the 40/1 Frenchman's Creek. Talented, but awkward, he just might be intrigued enough by the Aintree obstacles to show his best.