It was a moment which summed up the conflicting emotions which often co-exist in the sport of kings.

On Thursday, during the Fox Hunters' Chase at Aintree, Katie Walsh's horse, Battlefront, collapsed and died from a heart attack after being pulled up at the 11th fence. Afterwards, the shocked jockey paid tribute to her fallen mount, saying: "We had many great days. He was a gent and I will miss him very much."

A second death followed yesterday when Little Josh was put down after suffering a broken shoulder in a fall four fences from home in the Topham Chase.

This afternoon, Britain and the racing world will once more be engrossed, excited but also apprehensive throughout the 2013 Grand National at the Liverpool circuit. There is a sense of nervousness among the equestrian set, following the death of four horses during the race in the last two years. John Smith have withdrawn their sponsorship and animal rights campaigners are growing more vocal in highlighting the dangers for those who tackle the imposing Becher's Brook and myriad other formidable obstacles.

Walsh, on Seabass is highly fancied, to become the first woman to win the National. If that happens, the 28-year-old Irish rider can expect to see her face plastered all over tomorrow's papers. Unless, of course, there is fresh tragedy to report. Lucinda Russell is one of the best-regarded trainers in her domain and the Scot, who gained a BSc Honours in psychology from St Andrews University, speaks passionately and articulately about the queasy symbiosis between triumph and tristesse on the turf.

"We value horses, we love horses, and we do everything we can to keep them safe," she said. "It is simply not true that anybody is complacent about the fatalities which have happened recently; if anything, Aintree is one of the most proactive places in the sport and their authorities are doing whatever they can to limit the number of incidents. One of the best innovations is the introduction of plastic fences rather than timber frames at Aintree.

"I know some people are calling for [the Grand National] to be banned and they are entitled to their opinion but the National will never be entirely free of risk, and that is because there is an inherent risk in nearly everything we do.

"If you speak to people in racing, you will soon discover nobody wants anything but the best for the jockeys and horses who take part. Does that mean we can guarantee the safety of all the participants at Aintree this week? No, it doesn't."

That tension is never far from the surface, even for many of us who regard the Grand National as being woven into the fabric of British culture. It is 40 years since Red Rum claimed the first of his three victories when he tracked down and eventually transcended the luckless Crisp during one of the most unforgettable vignettes in sport.

Yet, for every lip-smacking slice of history, there have been other moments where creatures have perished. Last year, it was the joint favourite, Synchronised, and According to Pete, who paid the ultimate price. Gavin Grant, the chief executive of the RSPCA, said: "The Grand National is on trial. I don't think the public will tolerate another race like those of the last few years. To many in the racing industry the death of Synchronised was a moment to wake up and say, 'Things have got to change'."

As Russell noted, they are changing. The start has been moved forward 90 yards, so that the horses will not become so agitated in the build-up. The core of the fences is softer than in previous years. Becher's is no longer covered in birch. And so on. The jumps are the same height and the ditches remain as treacherous as ever, but Russell is correct in asserting the race is a far cry from how it was in 1999, let alone when it began in 1839.

"Nothing stands still but there are thousands of us down here again this year, millions will be watching it on TV, and the whole nation will be gripped," she said. "There is always a new story at Aintree and I believe this could be Katie Walsh's year to write a new chapter. She came third last time, Seabass is an excellent horse, and they both know their way around Aintree. The standard of the women involved in racing is getting better and better."

A hush will descend over the UK late this afternoon. Millions of pounds will be invested by the cognoscenti and mug punters alike and fingers will be crossed when the long trek commences. Yet there are no certainties that bones won't be broken and lives imperilled. Is that justified? Possibly. What isn't in doubt is that if the National lottery keeps serving up fatalities, the race's number will eventually be up.