The first day of the Grand National meeting was today overshadowed by heavy rain, foot-and-mouth worries and the death of a former winner.
Dark clouds loomed over the Merseyside course and a light rain, which started at about 9 a.m., grew heavier throughout the morning.
The afternoon's racing was hit by several heavy showers.
Course officials said the poor weather may have deterred those who had not already paid for tickets.
Some 17,900 punters attending the first day's racing, slightly under course predictions of 18,000 to 22,000 people.
Aintree spokesman Mr Nigel Payne said: "In a sense the cancelling of Cheltenham has been working in our favour. "It has massively boosted advance bookings, although we are still down by about 5 per cent."
Race-goers and trainers entering the course were also delayed by measures to avoid the spread of foot-and-mouth.
The foot-and-mouth precautions were in addition to extra security measures introduced after the 1997 IRA bomb hoax.
Aintree bosses also reacted with sadness to the death of 1999 Grand National winner Bobbyjo.
The Irish-trained horse was until recently a likely contender for this year's race but was put down on Tuesday afternoon after complications during an operation on a broken bone.
PA