Champion jump jockey Tony McCoy has sparked a massive gamble by choosing Blowing Wind as his Grand National ride.

The surprise choice from 10 runners for trainer Martin Pipe had the bookies running for cover.

But not before William Hill had laid two bets to win a total of �100,000.

One punter staked �500 each-way on the horse at 50/1 while another had �1,000 each-way at 40/1.

Hills, who had taken little money for Blowing Wind beforehand, cut his price to 20/1.

McCoy has won the riders' title five years on the trot, but in each of those seasons he has failed to complete the world's most famous, and demanding, steeplechase.

He hopes this time he will be successful.

McCoy decided on Blowing Wind after walking the Grand National course on Thursday morning.

Heavy overnight rain and showers on Thursday have made the ground soft.

Blowing Wind's last run was a win on heavy ground at a two-miler at Sandown.

McCoy, stable jockey for Martin Pipe, had 10 horses to choose from.

These included Dark Stranger, who he was briefly on last year before falling at the third, and leading contenders Northern Starlight and Exit Swinger.

Amateur jockey Tom Scudamore, son of former champion jockey and now BBC commentator Peter Scudamore, will ride Blowing Wind's stable-mate Northern Starlight, a 28/1 shot.

Catch the big race live on BBC One, Five Live and Sport Online at 1545 BST/1445 GMT on Saturday.