Bookies William Hill are predicting a gloomy £100million payout in this Saturday’s Grand National if Champion Jockey Tony ‘AP’ McCoy flies home with another victory in the famous race.

The BBC Sports Personality of the year has reunited with last year’s winner Don’t Push It – and the bookies are bracing themselves for a lethal blow if history repeats itself as support began to wind-up for the 11-year-old.

As punters plunged onto the top-weight Hills have been forced to cut the odds to 11-1 from 14-1 on Friday, and are bracing themselves for a mega-payout if he becomes the first horse since Red Rum to take back-to-back renewals.

Kate Miller, spokeswoman for William Hill told Bettingpro: ‘’ Support for Don’t Push It is building by the hour and he’s the best-backed horse of the last 24-hours. McCoy burnt us to a crisp last year with his win, and it’ll be £100-million hangover if he does it again.’’

Others runners supported over recent days include the Sir Alex Ferguson-owned What A Friend – whom William Hill are offering enhanced odds of 14-1 for any Man Utd fan producing their season ticket in any one of Hills’s 2400 bettinng shops, and Ballabriggs – who could crown a fairytale moment for Donald McCain – son of legendary Red Rum trainer Ginger McCain. 

John Smith’s Grand National (William Hill Bet): 9-1 The Midnight Club, 11-1 Don't Push It, What A Friend, 12-1 Backstage, Oscar Time, Silver By Nature, 14-1 Ballabriggs, 16-1 Big Fella Thanks, Quinz, 20-1 Arbor Supreme, Niche Market, 25-1 Becauseicouldntsee, Bluesea Cracker, 25-1 Character Building, Hello Bud, Majestic Concorde, State of Play, 33-1 Calgary Bay, Chief Dan George, Tidal Bay, West End Rocker, 40-1 Skippers Brig, 50-1 Comply Or Die, Dooneys Gate, Golden Kite, In Compliance, Or Noir de Somoza, The Tother One, Vic Venturi, 66-1 Can't Buy Time, Grand Slam Hero, Killyglen, King Fontaine, Ornais, Royal Rosa, Surface To Air, 100-1 Quolibet, That’s Rhythm, 150-1 Piraya, Santa’s Son (EW ¼ 1,2,3,4)