Rupert Wakley, in his first season as a professional jockey, has been handed the mount on Betty's Boy in the Martell Grand National next Saturday.

Wakley, who rode 28 winners last term and finished runner-up to Seamus Durack in the amateur riders' table, has had 27 successes so far this season.

He has some experience of the Grand National, having partnered the outsider Hillwalk, who was pulled up before the 17th fence in last year's race.

Betty's Boy landed the William Hill National Hunt Handicap Chase at the Cheltenham Festival on his latest start in good style and his trainer Kim Bailey said: "He's come out of the Cheltenham race well and hopefully it will be a dry week - the better the ground, the better for Betty's Boy. He worked this morning and is in good form."

Betty's Boy is currently a 33-1 chance for the Martell Grand National with William Hill.

Paul Nicholls, who topped the £1 million prize-money mark for the season when Father Krismas won at Plumpton on Saturday, is preparing Double Thriller, the 7-2 favourite with William Hill and 20-1 chance Belmont King for the race.

"Double Thriller is a ridiculous price, but it is irrelevant, it doesn't affect anything - the horse is in great form," Nicholls said on Saturday. "Belmont King would need it to dry up to run in the National otherwise he will go to Ayr for the Scottish Grand National."

Double Thriller's jockey, Joe Tizzard, is also in top form having landed a treble at Sandown on Tuesday and at Plumpton on Saturday.

Nicholls added: "Joe is in good order and riding well with two trebles in a week which is good for his confidence."