This year's edition of the Grand National steeplechase has been cancelled in response to the coronavirus pandemic, the Jockey Club said on Monday.
The National is the centrepiece of the annual three-day meeting at the Aintree course near Liverpool, but this year's April 2-4 schedule has now been scrapped as a response to the spread of COVID-19.
"Following the Government's new public health guidance regarding avoiding social contact and stopping non-essential travel, and its statement that emergency services are withdrawn from supporting mass gatherings from tomorrow, the Jockey Club has decided that it is no longer appropriate to stage the event," said a statement.
Jockey Club Racecourses, which runs Aintree and a number of the UK's leading racecourses, had been looking at the possibility of running the National behind closed doors with minimal staff on site.
But it said the latest government information on the measures needed to contain the virus have led it to believe this is "no longer a viable consideration".
Sandy Dudgeon, senior steward of The Jockey Club, said: "The Randox Health Grand National Festival was just three weeks away and it's very clear to us it will not be possible for the event to take place. Public health must come first.
"I know this is hugely disappointing news for the many people who work in our sport and the many millions who were looking forward to this year's event, but very sadly these are exceptional times and this is the responsible thing to do."
Monday's announcement means Tiger Roll's attempt to equal the three Grand National victories of Red Rum, the race's outstanding horse of the 1970s, will be delayed by at least 12 months.
It may also lead to a change in policy at the British Horseracing Authority, with the national governing body having said earlier Monday that racing would carry on behind closed doors after the sport was widely criticised for allowing over 250 000 spectators to attend last week's showpiece Cheltenham Festival.
Cancellation of the Grand National will come as a blow to the British betting industry, with millions of pounds traditionally gambled on the race which represents a 'once a year flutter' for many people who would not otherwise bet on racing.