In a world where flamboyant headpieces and carefully-cut waistcoats are as ubiquitous as the high-society chatter that fills the air, attending races at Ascot is, in the words of one curt official, a formal occasion and "not one where you might dress as you would a nightclub".

But such belligerence was met with outrage after a new policy of applying orange stickers to racegoers who failed to meet the stringent dress code turned into a PR disaster and resulted in Ascot having to pay out thousands of pounds in refunds.

Under the new rules, implemented for the first time on Saturday, men in the premier enclosure were asked to wear a jacket and tie, while women were instructed to dress smartly. Those failing to do so had orange stickers applied to their entrance badges, with about 200 attendees forced effectively to parade their fashion faux pas. Organisers said the stickers were intended to show other stewards who had already received a warning. But it backfired when humiliated guests lodged a series of complaints. One dubbed the stickers "naughty boy badges", while another said the idea was "patronising and disgraceful".

Charles Barnett, Ascot's chief executive, said: "It is clear we let down many premier enclosure customers with a well-intentioned but misguided policy." He said all premier enclosure visitors would receive a refund.