Multiple champion jockey Tony McCoy will delay a decision on his mount for Saturday's Grand National until the last moment, reports said Tuesday. McCoy, who won the Aintree spectacle in 2010 on Don't Push It, is deliberating between Irish challengers Colbert Station and Double Seven. Both run in the Don't Push It colours of Irish owner J.P. McManus and were among the 65 horses left at Monday's declaration stage for the gruelling four-and-a-half mile (7.2 kilometer) steeplechase. Frank Berry, racing manager to McManus, told The Guardian newspaper that McCoy would make up his mind "about half an hour before the jockeys have to be declared" on Thursday. The record-breaking Northern Irish rider was on board Colbert Station last year. McCoy came off at The Chair, which is considered the tallest and toughest of the fences that horses have to negotiate. Berry added: "He (Colbert Station) is very well and Ted (Walsh) is happy with him. "We have Double Seven who has had a fantastic summer. He's won five and if the ground turned up good I'd say it would be a toss up between Colbert Station and Double Seven." Teaforthree is 8-1 favourite for Saturday's Aintree spectacle which breaks the £1 million ($1.6 million) prize money barrier for the first time. Trained in Wales by Rebecca Curtis he finished third to the since retired Auroras Encore last year. The weights are headed by Tidal Bay who is bidding to become the first topweight to triumph since Red Rum in the 1970s. At 13, Tidal Bay is also aiming to become the oldest winner since Sergeant Murphy in 1923. On Thursday the field will be whittled down to a maximum 40 runners which will include Nicky Henderson's 2011 Cheltenham Gold Cup winner Long Run, 14-1 second favourite. Another contender figuring prominently in the ante-post betting is Monbeg Dude. The 2012 Welsh Grand National winner is part-owned by former England rugby captain Mike Tindall, whose wife, Zara, Queen Elizabeth II's grand daughter, has played a key role in helping improve the nine-year-old's jumping. Source: AFP