Kate Middleton: How much fun are royals allowed on tours abroad? Etiquette unveiled

However, there remain rules in place, for instance around fashion.

“If a member of the Royal Family is at a working event, even though it is a relaxed setting, they will dress appropriately for the occasion, such as trainers if they will be running and taking part in a game such as football or cricket,” explained Chertoff.

If Kate and William travel with their children, they too will have their own etiquette rules which become stricter as they get older.

“Children are children and while they will be raised, like any child would be, on proper behaviour – such as saying thank you and how to use cutlery correctly,” said Chertoff.

“As they get older they will be informed of what is expected of them at activities and events, including where photographers may take photos of them, or who they are meeting and the appropriate greeting in the country they are in.”