British bookmakers will donate over PS2.6 million ($A5.3m) to NHS charities from profits on the Virtual Grand National, with almost five million people tuning in to watch the race.

With the real thing cancelled because of the coronavirus pandemic and racing on hold until at least the end of April, the computer simulation captured the imagination in a special program broadcast on ITV.

It proved to be a virtual epic, with the Christian Williams-trained Potters Corner (18-1) clinging on under teenage rider Jack Tudor to hold off the challenge of Walk In The Mill.

ITV said almost a third of all viewers watched the race, with the show peaking at 4.8 million, 30 per cent of the overall television audience.

Bookmakers had helped boost interest by announcing all profits would be donated to NHS Charities Together, the umbrella organisation which represents over 140 National Health Service charities.

The Betting and Gaming Council - which will also donate profits from bets placed in Ireland to Irish charities, hopes further money may be raised from successful backers donating some of their winnings.

"I'm sorry we couldn't have the real Grand National to find out if Potters Corner would have won or whether it would have been an historic three in a row for Tiger Roll, but at this time of need the nation used the day to come together and back our NHS," chief executive Michael Dugher said..

"It's also fantastic that the Jockey Club will be donating 10,000 tickets to the NHS and social care sector in Merseyside for the first day of the 2021 Randox Health Grand National Festival at Aintree."

"Winning" trainer Williams said he was obviously delighted with the result.

"It's great and great to cheer everyone up in tough times," he said.

"I think even people from outside of racing were tuned in.

"It was something for people to cheer on, people are stuck in their houses and it probably got a good viewing. It was something to watch together and have a bit of banter leading up to it."