To the casual observer, the competition is a grand masquerade of towering headwear and vertiginous footwear, as women gather near the parade ring hoping to receive the prized tap on the shoulder from the scouting judges. And no expense is spared (nor dignity in some cases), as these women attempt to totter all the way to the finish line.

So popular have the events become, many ladies' days are preceded by preview evenings . . . in which teams of stylists take guests through the latest looks for the season . . .

and a celebrity 'racing fashion ambassador' is christened each year . . . this year TV presenter Kathryn Thomas holds the title.

"Ladies' days have become a bit of a phenomenon, " agrees Tamarisk Doyle, PR manager for Horse Racing Ireland. "They're so popular . . . everyone loves to dress up and have a glam day out. At almost every festival there is a ladies' day and it has become the biggest day of the festival."

"It's a stylish event but it's not just about dressing up to win a prize. People like dressing up anyway. It's a long, fun day: have a bet, go to the Champagne Bar, meet your friends.

There's no dress code in Irish racing so you can wear whatever you like . . . it's all about your own individuality."

The Best Dressed Lady is a regular fixture in horseracing countries such as the UK, Australia and the United Arab Emirates and the general rule is that would-be contenders must first wait for the tap on the shoulder from the judges who circulate the racecourse looking for the most stylish ladies. The one exception is the Dublin Horse Show, in which women are encouraged to enter themselves in the competition.

The event grows in popularity each year, with greater prizes giving rise to greater competition, while a host of high-profile figures from the world of fashion are drafted in to form the judging panel and luxury brands brought onboard to line up the prizes.

Newbridge Silverware, who have sponsored the Best Dressed Lady at the Punchestown Festival for the last three years, take the prize for overall extravagance. The face of the brand, model Yasmin Le Bon, holds court as lead judge, while a staggering prize of 30,000 in Newbridge vouchers goes to the winner and 5,000 to the runners-up.

"This year was our third time associated with it, " explains marketing director Phil Donnelly, "and in that time the whole profile of the Best Dressed at Punchestown has changed dramatically. It's the ultimate day in the racing calendar. Year on year, they're experiencing significant growth purely because of our involvement in it."

This year, Corkwoman Karen Murphy walked away with the Newbridge prize. Her outfit was a vintage piece originally handmade by her mother in the '70s. "Straight away we knew that there was something different about it, " says Donnelly. Of course, not all winners take the prize so effortlessly. As with any competition, the event also attracts some more seasoned competitors: in this case a group of women dubbed 'The Pros' by many on the circuit. Often seen as a cloud of colour coordination, these women circulate the paddock area with military precision to put themselves in eyeshot of the judges.

They'll stand in prime vantage points, smiling stiffly, champagne flutes tightly clenched and eyes darting wildly trying to single out a floating judge. When they eventually receive the perfunctory tap on the shoulder, it's usually greeted with a prerequisite look of feigned surprise.

"There are a lot of ladies who go on the circuit, who dress up especially for it and make a career out of it, " explains model and judge Andrea Roche. "'The Pros' would be more on the ball on where to stand and who are the judges. So it's great to pick a girl who genuinely has no idea, who's just running from A to B, busy in her own little world and not as aware as somebody else. I try to look for somebody who looks like they haven't tried too hard. Somebody who has a bit of flair, who's wearing something quirky or different, not a typical racing outfit, I suppose."

Stylist Celia Holman Lee, another regular judge on the Best Dressed Lady panels, agrees: "The only thing I'll say is yes, these women are there in the throes but they do set a standard, in a sense that they've all won before. That's why they're called 'The Professionals'. But they look fantastic, that's why whoever beats them has to look better than them. They come along and from the top of their heads to the tips of their toes they are magnificently coordinated. You have to give them that and I think the race meetings would be a lot duller without them."

If 'Pro' status is confirmed on past form, then Best Dressed regular Faith Almond is undoubtedly the champion . . . though the Carlow woman is quick to palm off the 'Pro' tag, insisting her true love is horseracing.

Almond won her first Best Dressed Lady almost 20 years ago but how many has she won altogether? "Ah sure, I don't know, maybe about 30 times, I don't count. I'm like the small farmer with the few acres: I've won a few holidays and a few diamond necklaces.

It's a great help towards the next outfit."

Almond now helps coordinate other women before race meeting and weddings.

"A couple of years ago I styled one girl who came in the final four in the [Dublin] Horse Show. I suppose it's something that just comes natural to me. . . I think part of success is dressing appropriate for the occasion.

My motto is 'style never goes out of fashion'."

Another woman whose style has caught the attention of the judges on countless occasions is Eva Hayes, a school teacher from Limerick. Hayes has been a racegoer since she was a little girl. "We were brought to the races since we were tiny tots, " she says, "and my mother would have always dressed up in hats and really elegant outfits, so we got a sniff of it there; we didn't know any better."

Hayes has gone on to win the competition five times and has been placed in the finishing line-up "maybe 15, maybe 20 times".

Among her prizes have been a diamond watch by Raymond Weil and a 3,000 shopping voucher for Kildare village. Her two sisters also began taking part two years ago.

"Mary has never won and Sarah, my twin, just won it at Tralee for the first time."

Hayes has also made a convert in her boyfriend, who recently partnered her to second place in the Best Dressed Couple competition at the Curragh. "He was wearing a Bertoni black and white pinstripe suit and I was wearing black and white pinstripe . . . we coordinated with each other. I was known at this stage so a couple from Galway who looked stunning, and had their suits made especially for the occasion, came in first place."

How does her blue-ribbon status rub off on the other competitors, I wonder. "They'll always be one or two greeneyed monsters, " she admits, "people who might say, 'She shouldn't have won that.' You see, you get people who spend a colossal amount on clothes and hats and there's a bit of envy if they don't win. There are women who dress head-to-toe in Prada, Gucci, Chanel and Philip Treacy . . . the works. I can only imagine that amounts to 5,000, easily. But that's part and parcel of any competition."

Holman-Lee also admits some sniping can pervade the parade ring. "You get a bit of it, " she concedes, "of course you do. But I think it goes on in everything. One particular time, as I passed a group of ladies, one of them pulled me aside and said: 'Are you blind, Celia?' I said, 'No, darling, I'm not, I gave it to a girl who should have won.'" The sniping is not confined to the competitors, however; the Best Dressed Lady also has its critics on the sidelines, women opposed to the competition on principle, with one well-known designer dubbing it a "jumped-up beauty contest". It's an opinion Holman Lee has yet to encounter. "Hand on my heart, I haven't experienced that, " she says. "With the Miss Ireland you would get swiped at there but never with regards the Best Dressed, never.

"I see women who wouldn't have a notion of the Best Dressed Lady, " she goes on.

"They just don't want to know about it and they're sitting in the hospitality tent, or in the Champagne Bar, and they look fabulous.

Then you see these ones who might not have any interest in the Best Dressed, gathering to see who we did pick.

"Standing at the Curragh and looking out at the parade ring, the horses are strutting their stuff and we're there posing with the feathers and the umbrellas and God knows what and we get the crowds . . . everyone looks around. Everybody dresses up: it's not about winning the prize, it's just a gorgeous occasion."