British bookmakers say the cancellation of the Grand National because of the coronavirus outbreak will be devastating to the racing industry.

Jockey Club Racecourses have announced the biggest betting race of the year - which would have featured Tiger Roll going for a hat-trick of wins - will not take place at Aintree next month.

Betting on the race is usually in the vicinity of STG300 million ($A602,647).

"The cancellation of the Grand National meeting is a devastating loss for everyone and will cost the racing industry millions at a time when we are already feeling the strain of a completely decimated sporting calendar," Unibet's Brett Williams said.

"But it goes without saying the treatment and care of those suffering, or potential sufferers, of the coronavirus is paramount and Unibet fully support the decision made by racing's governing bodies.

"This is an unprecedented situation we are all facing and it is extremely important the whole industry pulls together and adheres to the guidelines and reacts accordingly to all advice issued

"All bets on the Grand National have been voided."

Simon Clare, PR director for Ladbrokes Coral, echoed Williams words.

"The Grand National is the biggest betting horse race of the year, so its cancellation is clearly a blow to the sport, to betting operators and to racing fans," he said.

Racing in England will go ahead behind closed doors this week after Scotland and Ireland moved to spectator-free racing last Friday.

The famous Cheltenham jumps festival went ahead last week with more than 250,000 people attending over the four days.