While the Royal Family have plenty of rules to stick to when it comes to performing their royal duties, not everyone knows about some of the more unusual rules or actions they have to take behind closed doors. When on royal state visits, or any trips abroad, it is believed members of the Royal Family take a bag of their own blood with them in case of emergencies.

It is believed both King Charles and Prince William take their own blood supply overseas with them, something that the late Queen Elizabeth II commonly did. This was revealed by royal expert Adam Helliker who said the supply would be topped up with “regular deposits”.

He told Fabulous Digital: "She will have kept the supply topped up with regular deposits on the months before a trip abroad.

"So it’s just like someone making voluntary blood donations - the difference being that she will be the only recipient if it’s ever needed - that ‘blue blood’ will never find its way to an ordinary patient."

On visits abroad, it is believed monarchs also travel with their own doctors should any incidents take place.

This is believed to be common practice for the royals when taking trips abroad, especially King Charles.

The King, who was diagnosed with cancer last year and is still undergoing treatment, is also believed to only travel when given the green light by his doctors.

Last year, His Majesty, 76, got permission from his medical team to pause his cancer treatment to allow him to undergo a state visit to Australia and Samoa.

The monarch was also given the green light more recently to do a state visit in Italy, which concluded this week.

While it is for his own good, His Majesty did once make a comment suggesting that doctor’s orders were, on occasion, holding him back. At an official dinner in Samoa last year, King Charles said doctor’s orders had made some of his lifelong ambitions to visit all areas of the Commonwealth a challenge.

Despite these restrictions seeming to annoy the monarch, it is believed the King has been acting on the advice of doctors as he continues to undergo cancer treatment.