Women attending posh horse racing event Royal Ascot have been told they must wear knickers, but not show them off.

The world-famous races, which start tomorrow, have for years been the pinnacle of racing style with their morning dress code.

But now bosses have been forced to launch an illustrated guide to the rules for the increasing numbers of chavs who are going to the races.

No-nos include skirts more than two inches above the knee, off-the-shoulder dresses, women showing off their midriffs and streaky fake tan.

Anyone caught breaking the rules in the  Royal Enclosure - where they could be rubbing shoulders with the Queen - now risks being booted out.