Protocol demands certain dress codes when interacting with Royalty, especially at functions that are officially representative of the nations the Royals serve. Remember that the Royals themselves are bound by these rules even if the public are not, so when the interaction is by invitation, then the guest is obliged to adhere to the dress code themselves. For this purpose we will now list the levels of dress code from casual to formal and the differences in day wear and evening wear.
Royalty, like all people have private lives and in most of these settings will merely wear casual clothes or clothes appropriate to the situation like bathing suits to the beach for example.
In a standard corporate environment or diplomatic setting in the day, the appropriate dress would be what is required in most office settings, a neat and stylish suit and tie for the men or coordinated pencil skirt suit or pants for ladies.
For a slightly dressed up feel during an outside day party, the cocktail dress code applies. This would be a morning suit or sport jacket and trousers for men and a short skirt and hat for the ladies. This dress code normally applies at horse races and afternoon tea or cocktail parties.
Day Formal with Hat
For officially formal events of state that happen during the day and for funerals a smart short length dress or skirt and hat along with morning suits or uniforms for men are required. In some cases even Knighthood Insignia may be required. This is sometimes the dress code for guests at a Noble wedding but for Royal weddings tiaras may be worn.
Evening Cocktail Formal
Formal evening wear without tiaras normally pairs with short dresses and tuxedos for men. This is normally the dress code for an early evening party that is not considered a State event.
Short Formal with Tiara
Evening Gown Formal with Tiara
A longer evening dress with tiara and tuxedos or uniforms for men is the standard for any titled person to wear to what one might refer a formal evening gala. These events, though formal, might not be a State affair but the particular event may require formal dress. Tiaras in this case are not always obligatory and sometimes entirely omitted like when the event is held at a hotel.
Ball Gown non-State Formal
There is such an event among Royalty as the Royal Ball. These events though very similar to the above mentioned event are considered Royal but not necessarily a State function. To a Royal Ball, tuxedos or uniforms are worn by men and the ladies are required to wear long evening gowns or full ball gowns, with tiaras. Knighthood Insignia are optional.
A State Evening Function is the second most formal event possible. The dress code is similar to the two above mentioned but members of Orders of Knighthood are required to wear their insignia if they are members of an order. Sometimes Chains of Office may also be worn.
An even more formal dress code is expected at certain State Evening Functions. Known as Court Dress, this is what is worn at State Banquets and for State Portraits. Uniforms, or traditional regional clothing is worn by men and ladies wear full length evening dresses. Normally symbolic tiaras and/or crowns may be worn along with Knighthood Insignia and Chains of Office.
There are only two events that require this dress code, they are a Coronation or Opening of Parliament. Here Court Dress applies with the addition of Robes of State. This dress code is also but rarely applied to State Portraits as well.