The official field of runners for the Grand National is finalised in the week before the race (8th April ). Until then we'll feature the leading horses in the. How One For Arthur won the Grand National to tire and a pack of five horses, with One For Arthur on their outside, started to close him down. The Last Samuri heads the final field of 40 runners in Saturday's Randox Health Grand National at Aintree. Sportsmail's Sam Turner analyses. Latest Grand National News. Horse Racing Resources Cheltenham Festival Races. Smart performer who was fifth in March's Cheltenham Gold Cup. B ut it's a bit of a circus. We've ark quick item slots together a list of the key traits which most National winners display. Nagging feeling that chance may have gone despite a close third in Becher Chase at Aintree in December.