The Aga Khan (r) arrives by carriage to attend Ladies Day on the third day of Royal AscotThe Aga Khan (r) arrives by carriage to attend Ladies Day on the third day of Royal Ascot June 22, 2006.Wed 22nd Ladies day at the ASCOT, England

Extravagant hats and fancy dresses were out in force on Ladies' Day at the Royal Ascot races, the colourful highlight of the prestigious five-day event.

Royal Ascot is one of the world's most famous meetings. Ladies' Day was attended by about 70,000 people gathered to sip champagne, have a punt and be seen at the glamorous pinnacle of the British high-society calendar.

Queen Elizabeth II and her husband Prince Philip arrived in the traditional horse-drawn open-top carriage procession past the newly renovated main grandstand. They were accompanied by the Aga Khan, the spiritual leader of the world's 15 million Ismaili Muslims and a keen racehorse owner.

The 80-year-old monarch threw many punters who bet on the colour of her hat by wearing the same hue as on Wednesday.

She wore a lime green hat decorated with pink roses with a lime green long jacket and matching skirt.

Punters had mostly placed their money on either red or white, with lime green closing at odds of 16 to one.

A spokesman for bookmakers Paddy Power said a betting representative was summoned to an audience with one of the queen's private secretaries where it was agreed that bets should close before the queen had chosen her outfit, to avoid accusations of insider dealings.

The spokesman said: "We may have been stung last year (when the queen wore brown) but, this time, Her Majesty kept the colour well and truly under her hat. Punters never expected to see two shades of one colour in a week."

The prestige Royal Enclosure's dress code is draconian: gentlemen must wear morning suits with a waistcoat and a top hat; ladies are "required to dress in a manner appropriate for a formal occasion". This means hats, no strapless dresses, and certainly no bare midriffs