It was still tough to make out exactly what was going on for much of the race as the fog descended like a blanket over the course.

Things had got so bad by the end of the afternoon that the last race had to be abandoned when visibility dropped even further.

But there was little mistaking the most impressive winner of the day as 15-2 chance Chauvinist burst into the lead around the final turn and was ridden out all the way to the line by Norman Williamson to win by 15 lengths.

Idaho d’Ox, a 50-1 no-hoper, stayed on out of the pack to grab second place from brave front runner Benbyas, with Tikram holding on for fourth.

Winning trainer Nicky Henderson saved his sympathies for stable jockey Mick Fitzgerald.

The pair had combined for a famous five-timer at Newbury in midweek but with Chauvinist handed a burden of just 10st for the race, Fitzgerald was forced instead to ride stablemate Valerio, who was tailed off when eventually pulled up.

“It’s tough luck on Mick as obviously he would have won on him, even with 10st 3lb or 10st 4lb,” he said.

“But you can’t go putting up overweight in races like these and we had really fancied Valerio. He just couldn’t handle the ground.

“Norman knew he would stay and even though he was a bit off the bridle round the turn he just kept on galloping.

“He has had problems with his knees in the past but we thought we had got him right again.

“I suppose we’ll think about the Supreme Novices’ now but he did only have 10st so you have to keep things in perspective.”

Williamson was enjoying a third success in the race, having scored at Leopardstown in 1997 with Master Pride and also in the first running at Ascot last year on Marble Arch.