The foot-and-mouth crisis looks set to hit the Powers Gold Label Irish Grand National with a Fairyhouse spokesman describing the chances of running Irish jump racing's richest race on its traditional Easter Monday date as "extremely unlikely".

The crisis has also forced the authorities in charge of April's other big racing festival at Punchestown to yesterday describe the Kildare track as "Fortress Punchestown". Course chief executive Charlie Murless explained: "Every plan is in action to safeguard the facility. Punchestown now looks like Fortress Punchestown. This is wartime. We're all on the one side against this terrible enemy."

The Fairyhouse track could be the first affected, with its four-day festival starting on April 15th already under threat from the current foot-and-mouth cases in these islands.

The Fairyhouse executive are already provisionally looking for alternative dates and the track manager, Dick Sheil, said yesterday: "It's extremely unlikely the meeting will go ahead on its scheduled dates. We are open to discussion about running the event at a later date, but there are no obvious opportunities in the calendar given Punchestown is just a week later."

The unease at Fairyhouse is due to the length of time racing would need to resume normal service, even if the foot-and-mouth crisis started to wind down.

A two-week incubation period for the disease could be followed by another month before confidence would grow that the virus threat had disappeared. In 1967, when no cases of foot-and-mouth were discovered in the Republic, racing stopped for 12 weeks.

Professor Joe Quinn of the Veterinary College in University College Dublin explained yesterday: "If you take a particular date after which there were no further outbreaks, there would be an incubation period of up to two weeks for foot-and-mouth. But the virus can survive for another month after that if the conditions are right. A cold and damp environment can allow it survive for up to a month."

Dick Sheil added: "The cut-off date for Easter is very near and we are holding our breaths. If foot-and-mouth is confirmed in this country we will be into a whole new ball game but if things are the same in a week we will be able to review the situation with more clarity."

Punchestown, which is due to start its own four-day festival on April 24th, will come under the same pressure soon if the crisis continues to grow, but Charlie Murless yesterday did not want to speculate on any possible postponement.

"We view everything with enormous concern but we have every faith the authorities will do whatever is necessary. These decisions must be taken at national level," he said.

Racing in Ireland last took place six days ago at Naas and racing was banned by the Government on Tuesday.