Grey horses have developed something of a magical status when it comes to Grand National betting with thousands of casual punters backing them each. Runners, riders, trainers and form - all the key details you need to know for Saturday's big race at Aintree. (Racecard number, horse, trainer. A field of 40 horses headed by The Last Samuri is set to contest the th running of the Grand National on Saturday. A win in February's Bobbyjo Chase at Fairyhouse captain cook one of only six runs over fences. Profile is a frustrating horse on an unrealistic rating. Armed police have been in attendance at the course during the three-day meeting which started on Thursday. Jockey AP Heskin Trainer T George Age Seven Weight 10st 12lb. Has not won since, becoming a byword for regression, but it might be time to take him seriously. Some decent runs this season including a fourth in the Paddy Power Chase at Leopardstown over the festive period.