There are now just 24 hours remaining until Prince George celebrates his 12th birthday on Tuesday, 22nd July, and with it comes a significant and controversial rule he must begin to follow.

By this time tomorrow, the eldest child of Prince William and Kate Middleton will be just a year shy of becoming a teenager, meaning he will be expected to take on more public-facing duties as he matures.

The Prince and Princess of Wales are also proud parents to Princess Charlotte, who is 10, and Prince Louis, who is seven.

As George is second in line to the British throne, following his father, he must start adhering to certain long-standing royal protocols as he prepares for his future role as King.

Although age 12 might seem quite young, Prince William had to follow these same traditions during his own youth, just as King Charles III did before him.

One particular rule that will take effect tomorrow has sparked division among royal family fans worldwide.

Prince George will turn 12-years-old tomorrow (GARETH CATTERMOLE/POOL/AFP via Getty Images)

The new rule dictates that George will no longer be permitted to travel with his father in order to safeguard the line of succession.

In simple terms, this rule is in place to ensure that, in the unlikely event of a disaster, such as a plane crash, there will still be an heir to the throne.

Although such scenarios are highly improbable, it is necessary to make preparations for any eventuality, ensuring the continuity of the royal line.

Understandably, some people find this rule outdated and unfair.

One Facebook user commented: “That's so old school—let him stay with his family,” while another agreed: “It's ridiculous given that he is the next King after William.”

Another questioned: “I think they do this to safeguard the Monarchy. But couldn't his mother accompany him? Or Charlotte?”

Others added supportive comments: “I hope he adjusts well to the separation. Good luck George, we are all with you in spirit” and “I thought they were modernizing their way of thinking. Why separate the children?”

George will have to travel separately from his father from his 12th birthday onwards (Samir Hussein/WireImage/Getty Images)

Meanwhile, another person remarked: “Too sad, even if it is the rule,” and someone else added: “Not fair. This rule is archaic and unnecessary! There's always someone next in line to the throne!"

However, other royal enthusiasts see the necessity of this rule and rightly point out that he can still travel with his mother and siblings.

One social media user noted: “His family has been in this position for years. He is fully aware of his role. I’m proud of him for handling it well.”

Another added: “Lol that's a standard practice to keep the next in line to the throne safe in case of emergencies. It's nothing unusual but common practice when royals use any form of transportation.”

“And he won’t be flying alone; his mother would always accompany him,” a third user pointed out.

Others remarked: “Awwwww. Sad really. But his Dad did it. He will be fine” and “It’s to protect the royal line. It's been a tradition for years! The Queen bent the rules once when Diana died!”

Someone else wrote: “He’s a future king, so his safety is paramount.”