ASCOT England (Reuters Life!) - Jockey Frankie Dettori has no doubts-- Ladies Day at Royal Ascot is a world beater for dedicated followers of fashion.

Sporting top hat and tails with a pink rose in his buttonhole, the ebullient Italian argued that when it came to elegant racing it was no contest. Ascot beat the Kentucky Derby and Arc day in Paris every time.

"Absolutely. At Royal Ascot we have had 300 years of practice," he told Reuters, reveling in the fashion extravaganza as women paraded in their finest for Ascot Gold Cup day. For Dettori this is "the Olympics of racing."

Fashion designer Jeff Banks, resplendent in purple waistcoat, agreed.

"What I love about British fashion is its witticism. In France they take themselves far too seriously and in Kentucky it is all about the money -- how much did you spend on that."

Admiring all the finery and fascinators around him, Banks said: "I've been designing for 46 years and I never get tired of it."

Royal Ascot, immortalized by flower girl Eliza Dolittle in the musical "My Fair Lady," is the High Society highlight of an exhausting summer season that stretches from the Chelsea Flower Show to Wimbledon and the Henley Royal Regatta.

For party-going poseurs, it is all about cutting a dash, seizing a brief moment of fashion fame as paparazzi prowl the track in search of the outlandish.

Royal Ascot was once so exclusive that divorcees were banned and ladies had to wear gloves. Today aristocrats are outnumbered by hedge fund managers and Ascot's "fashion police" are on red alert for any sign of mini-skirts and midriffs which are banned.

Ardent racegoers are there to revel in one of the world's greatest racing festivals. The socialites just want to be seen.

That aggravates former jockey turned BBC commentator Willie Carson. "I am not into fashion when I am horse raciong," he said. "But we are always very glad that the ladies come to see our beautiful thoroughbreds."

But Ascot raceourse manager Charles Barnett is phlegmatic about the mix.

"There is a great cross-section of people who like racing and people here just for the fashion. Everyone mixes together."

Royal Ascot is given priceless social cachet by Queen Elizabeth who parades up the course in an open-top landau before racing every day.

In the 18th century, Queen Anne first spotted Ascot's potential when riding in the forest near Windsor Castle. The course was opened in 1711.

Betting is an essential ingredient in the Ascot cocktail and bookmakers enter into the spirit of the fashion parade - odds are offered every day on the color of Queen Elizabeth's hat.

(Editing by Paul Casciato)