Animal rights activists planning protest at Grand National

The largest demonstration by animal rights activists against the Grand National will be staged today as the horses run against a background of unprecedented security measures.

As part of a horseracing awareness week, Animal Aid will co-ordinate what it believes will be the biggest peaceful protest seen at Aintree. It comes after two horses died on the first day of the meeting. "The Grand National brings shame on Britain as a nation of animal lovers," a spokesman said. "If you can't bear to watch the horrors of the race unfold on your television screen be there on Saturday to make a stand against it."

Merseyside police have been planning for the biggest day of the racing calendar for the past six months. "The world is a different place since 11 September," said Supt Justine Curran. "We have developed very robust contingency plans so we can respond to anything that might happen."

The plans include a refined system for evacuation, a process last required in 1997 when Aintree had to be cleared because of a bomb hoax. The visible deterrents today will be dogs, mounted horses and helicopters, as well as uniformed officers. There will be airport-type security on the way in. Yesterday, the system meant a wait of up to 45 minutes for entry.

The three leading National Hunt jockeys will have to pass a medical examination this morning if they are to take part in the 155th running of the steeplechase. Tony McCoy, who broke the 65-year-old record for the number of winners in a season on Tuesday, Richard Johnson and Mick Fitzgerald all suffered injuries yesterday on the second card.

McCoy, who has ridden 272 winners this season, came to grief twice, falling from Northern Starlight and then Iznogoud, when he grazed his nose. Johnson has a damaged knee, while Fitzgerald was shaken by a tumble on Lord of the River. All three are expected to be passed fit.

Today also represents the first tax-free Grand National and bookmakers are expected to turn over a record £120m. The big race favourite is likely to be Blowing Wind, as long as McCoy passes his medical.