The numbers are nearly as breathtaking as the sight of 34 horses soaring over Aintree’s famous fences. Before Saturday’s Grand National, a third of adults in Britain will place some sort of bet on the world’s most famous steeplechase. £150m will be wagered in total. And six million will then tune in for the spectacle.

But amid all the noise and fanfare surrounding the 177th running of the “people’s race”, organisers are increasingly engaged in a delicate high-wire act. Because the more they try to ensure the thrills come without horrific spills – and potential deaths – the more they upset traditionalists, who fear that the National has gone too soft.

Such calls have become increasingly loud after last year’s race, which had no fallers, no fatalities, and the highest number of finishers since 2005. Timeform, the bible of horse racing, was among those to wonder whether making the National safer had not only stripped it of its fiendish difficulty but its magic.

“The old ‘Wooden National’ was primarily a test of jumping,” one Timeform writer lamented. “That is no longer the case. The ‘Plastic National’ is only slightly different to other top marathon chases.”

Yet at Aintree on Friday, race organisers were insisting that the marathon race, which takes in four-a-quarter miles and 30 fences, had moved with the times and changed for the better.

“I have friends who have been in the sport for 50 years, who say that it has lost its character, and is not what it was,” Dickon White of the Jockey Club said. “And while I respect their opinion, I thought last year was a fantastic spectacle, with so many horses in contention until the final fence. And the reality is, the race has always evolved.”

That is certainly true. In the first National, in 1839, horses had to jump a stone wall, cross a stretch of ploughed land and finish over two hurdles. While in the 1950s the Manchester Guardian warned that the race “in its present form cannot in all public decency be tolerated any longer” after only 36 of the 192 horses which had started in the previous five Nationals finished, and nine had been killed.

More recent changes, which have included making the fences easier and reducing field sizes down from 40 to 34, are designed to sustain the drama but dial back on the danger. Which, given it is only two years since National made front page news when the 118 members of the activist group Animal Rising were arrested for trying to stop the race, is surely no bad thing.

And while the race isn’t as popular as it was in the late 1990s, when 10 million viewers would watch, it is still notably resilient. The Sun’s man at Aintree said that his paper had put on over 200,000 over four days for last month’s Cheltenham Festival and expected Saturday’s paper to be one of the bigger sellers of the year. And the Star’s man reckoned they would also get a 20% uplift in sales too.

Meanwhile bookmakers say the allure of the race remains strong. “We track all the figures so we know that in terms of turnover, there will be £150m bet on the Grand National, which is six times bigger than the next biggest betting race, which is the Cheltenham Gold Cup,” said Simon Claire of the bookmakers Coral.

“Meanwhile a third of the adult population will have a bet, or have someone place one for them. So it remains an incredible British institution in a world where these things often get done in by the passage of time.”

That, insisted Clare, that includes plenty of once-a-year punters. “Bookmakers aren’t shy of trying to recruit customers,” he added. “But the industry will take bets from hundreds of thousands or people tomorrow that we know will not be back again for 12 months. It’s a bit like selling turkeys at Christmas. You know that everyone wants them. But when it comes to June, it won’t be the case.”

Meanwhile as the debate about safety rumbles on, the British Horseracing Authority says it is trialling new software that uses AI to mitigate the risk of injuries and falls.

The BHA’s acting chief executive, Brant Dunshea, said they had been using an app called Sleip, which tracks a horse’s gait over time, and flags up if it changes.

“What this technology does is it helps inform decision making, because it takes a recording of the horse’s gait and then uses artificial intelligence to map over time whether or not there’s been a change,” Dunshea said. “If there has, it could give the veterinary officers a reason to look more closely at a particular issue.”

Every horse running at Aintree will also undergo pre-race examinations as part of the trial, and Dunshea says the BHA is also looking at using wearables to track a horse’s heart rate, stride length and other variables during races.

Meanwhile, White also insists the Jockey Club won’t hesitate to change the race again if necessary – whatever traditionalists think.

“We want to ensure that we are putting on the most exciting, the best race we possibly can,” he said. “After every every Grand National we sit down and review what went well, what didn’t go so well. And we won’t be afraid to make changes to ensure that the race is as safe as it possibly can be.”

None of that will matter to most watchers when the starter’s flag drops at 4pm on Saturday . For them the spectacle, and the chance to win their office sweepstake or a rare bet, will be the only thing on their minds.