The Grand National Aintree 2016 is set to start and Many Clouds is bidding to to win back-to-back races.

This year’s jump racing spectacular kicks off on Thursday and the best jump horses in Britain will compete for three days April 7-10, ending with the Crabbie’s Grand National race on Saturday. It is estimated that around a quarter of UK’s population will be placing a bet on a runner, however large or small.

Many Clouds is the favorite to win the £1m Crabbie’s Grand National at 8-1 after storming to victory in 2015 and looking even more dominant during a recent outing. The horse, owned by businessman Trevor Hemmings, attempts to become the first since Red Rum in 1973 and 1974 to win back-to-back runnings of the famous steeplechase, first staged in 1839.

But the National always throws up surprises and any one of the declared runners is in with a shot of upsetting the odds. Other leading hopefuls include The Last Samuri, which scored an impressive victory in the Grimthorpe Chase at Doncaster, is at 10-1. Winner of Betfair Ascot Chase Silviniaco Conti is at 11-1, and Holywell, at 14-1, boosted his National claims after winning second place in the Cheltenham Handicap Chase this year.