Jockey AP McCoy has bookmakers fearing a £50m loss as he prepares to ride favourite Shutthefrontdoor in his final Grand National on Saturday.
The 19-time champion, from Northern Ireland, will retire if he wins on a record 20th appearance in the race.
Punters are predicted to back his horse, trained by Jonjo O’Neill, so he becomes the shortest-priced National favourite since Red Rum 40 years ago.
Six of last year’s top seven, including winner Pineau De Re, are in the field.
What’s the National chat?
While much of the focus is on McCoy, there is plenty of other interest in the marathon contest which sees the 39-strong field face 30 fences over nearly four-and-a half miles.
Nina Carberry will bid to become the first female jockey to triumph in the 168th running of the race which features iconic obstacles such as Becher’s Brook and The Chair.
Carberry, 30, rides 25-1 chance First Lieutenant for Irish trainer Mouse Morris two days after she won the Foxhunters’ Chase over the National fences with On The Fringe.
Last year’s runner-up Balthazar King and fifth-placed horse Rocky Creek are among leading challengers.
was cut on Friday morning after outsider Carlito Brigante was declared a non-runner by trainer Karen McLintock because of lameness.
The news came after the 09:00 BST cut-off point for the employment of a reserve to replace the horse, who was to due to have been ridden by the race’s most senior jockey, 42-year-old Brian Harding.
End of an era
McCoy shocked the racing world when he announced in February, having ridden his 200th winner of the campaign, that he would retire by the end of the season.
His record-breaking career has brought a total of more than 4,300 victories despite a heavy toll of broken bones and a punishing diet to keep his weight down.
The 40-year-old admits he would love to carry on riding, but wants to go out at the top. If he does not win the National, McCoy will bow out a fortnight later at Sandown.
“It would be lovely to win the National, but that would also mean I stop riding,” he said.
A fairytale farewell?
McCoy has effectively been on a two-month farewell tour with racecourses in Britain and Ireland honouring him as he rides at their track for the final time.
The rider has been patiently signing autographs and posing for pictures, with racegoers writing good luck messages on a special tribute wall at Aintree.
But despite being favourite, the odds on him landing a fairytale final win are against him.
He has only won the National once, at the 15th attempt
a victory that helped him secure the BBC Sports Personality of the Year award.