Fashion is a huge part of Ascot's culture, and dressing appropriately for the occasion is a must. Discover our dress code for Royal Ascot and each season here. Royal Ascot 3 piece morning suit for men for the Royal Enclosure. Buy at Moss Bros online - free delivery. turn of the 19th century dictated the dress for men in the Royal Enclosure. His sense of style is still A waistcoat and tie (no cravats). • A black or grey top hat.