Fancy a flutter on a woolly jumper in the Sheep Grand National?

(CNN)From office sweepstakes to gambling grannies, Grand National fever is sweeping the UK ahead of the nation's world-famous horse race at Aintree on Saturday.

A record-breaking $219m is expected to be laid in bets across the globe on which colorfully named horse will master the fearsome fences over the four-mile course.
"It is the biggest betting event of the year by a long way," Mark Pearson, of British bookmaker Betfred, told CNN.
    "With a worldwide television audience of 600m in 2014, it is simply the world's biggest race."
    Irish jockey Tony McCoy will be the star attraction at Aintree as the multiple champion jockey races in his final Grand National on mount Shutthefrontdoor.
    But for those looking for an outside bet, then the rival Grand National Sheepstakes in Devon could be just the ticket.
    Grand National fever is so entrenched in the UK that some ideas are a little barmier (or should that be baa-mier?) than others.
    Visitors to the Big Sheep family attraction in Devon on Saturday can place their bets on six of the best jumping sheep, including Woolly Jumper, Red Ram and Sheargar.
    The racy sheep, which jump over show jumping poles, must be careful not to unseat their knitted jockeys.
    Ascot, home to the prestigious royal flat racing meeting in June, also got in on the woolly races, by staging the Lamb National last month.
    There was even a royal presence for the novice hurdlers as Prince Charles and Camilla, Duchess of Cornwall watched from the sidelines.
    "They did appear to be having a great time," Nick Smith, Ascot Head of Communications and International Racing, told CNN.
    Sheep racing events are an unlikely success despite the dangers that the sheep will just follow each other aimlessly around the course.
    "There's a sheep dog. They wouldn't do it on their own," laughed Smith.
    "If anyone can get a sheep to jump a fence without a sheep dog I'm be very, very surprised. The sheep dog is the key talent in this operation.
    "Having said that one or two of the lambs got a bit lost and the sheep dog had to round them up."
    Could sheep racing ever usurp horse racing in the hearts and minds of the betting public?
    Smith, for one, was quick to scotch the idea that sheep racing could be a regular fixture of the Ascot race calendar.
    "It was a novelty event," he explained. "The chances of anyone watching a sheep dog race as a fan and transferring that into an interest in horse racing is nil."