This week, the Duchess of Cambridge and her husband, Prince William, are on a Caribbean tour. However, astute fashion observers may have noticed she stepped out of line by disobeying royal protocol. Kate delighted the people of Belize by wearing a floral Tory Burch dress in the country’s flag colours of red, white, and blue.

She did, however, violate one of the monarchy’s dress-code rules by wearing open-toed footwear, which is considered too casual for royal engagements and official visits.

Kate’s shoes also had a wedged heel, which the Queen dislikes and has advised working members of the royal family not to wear.

Lynnette Hecker, a royal fashion expert, owns Lovely’s Vintage Emporium, which supplies clothing to celebrities such as Holly Willoughby, Niki Minaj, and Dawn O’Porter.

“There’s no actual rule book written down,” she says, “but there are unspoken rules, just like in any family.”

“When people like Kate or Meghan join the royal family, they are usually taken to one side, usually by a chamber maid, and told what is acceptable and expected.”

“So, they have a choice about what they wear, but it’s not really a choice.”

“When it comes to open-toed shoes and sandals, the etiquette is that they are too casual.

“Kate usually breaks this rule when she attends a Hollywood or red-carpet event, but she usually wears a long dress so it’s not too obvious.”

“I also believe Kate has Diana’s quality of thinking about her surroundings and dressing appropriately for them.”

“It would not have been practical or appropriate to meet people in Belize or walk on sand in heels.”

It’s not the first time Kate has flouted the dress code.

She also wore wedges during the Olympic Games relay in 2012 and in 2019 when she visited the children’s hospice The Nook Centre in Norfolk to plant a sensory garden.

Kate, 40, also disobeyed another royal rule requiring women to wear tights with their dresses.

However, with temperatures on the Central American island averaging 28 degrees Celsius in March, this may have been more for comfort than for style.

Other rules include wearing only natural-looking hair and make-up, covering shoulders, wearing skirts no shorter than knee-length, and never taking off a coat in public because it is ‘unladylike.’

Rules must also be followed by the male members of the family.

Boys under the age of eight are required to wear shorts rather than trousers, which are reserved for’men.’

They also dress in military attire for special occasions and holidays such as Remembrance Day.

William, 39, and Kate are on a Caribbean tour to commemorate the Queen’s Platinum Jubilee this year.

Kate’s footwear gaffe occurred on the second day of their trip to Belize, when they visited the village of Hopkins and were treated to a ‘welcome’ performance.

They spent the day being fed by a local celebrity chef and dancing with the Garifuna community in Hopkins, Belize, which has a population of 1,000 and is frequently voted the “friendliest” village in the country.

Wills and Kate also planted a copper pod, a yellow-flowered ornamental tree.