The meaning behind the symbols 'GR' and 'ER' on British postboxes has only recently come to light for many people.

Postboxes in the UK are well-known red pillars used as public mailboxes for sending letters and parcels. They are famous for their distinctive design and bright red hue, which can be traced back to a decision made by the UK Post Office in 1874.

In addition to their color, postboxes often display the initials 'GR' and 'ER', leaving many wondering about their significance.

The UK Postal Museum has shed light on the meaning of the symbols found on British postboxes, which many people were previously unaware of.

According to the museum, the symbols on the front of the postboxes are royal ciphers that represent the monarch who was on the throne when the postbox was installed.

These symbols have been in use since the reign of Queen Victoria and are part of the postboxes' design.

As King Charles III's coronation approaches, some individuals are knitting royal toppers that portray the King and Queen Consort Camilla to decorate postboxes, while others are discovering the royal ciphers on postboxes for the first time.

The use of royal ciphers on postboxes dates back to 1852, according to The Postal Museum. The ciphers signify the monarch on the throne at the time of the postbox's installation, allowing them to be dated.

The museum also explains that instead of replacing the old postboxes with new ones when the monarch changes, new ones are simply added to the existing ones, leading to the wide variety of postboxes found throughout Britain.

Postboxes displaying Queen Victoria's cipher, 'VR', are the oldest, dating back to her reign from 1837 to 1901.

During Queen Elizabeth II's reign, postboxes bear the cipher 'EIIR', which is an abbreviation for 'Elizabeth II Regina' (Regina translates to "Queen" in Latin). For King George V, postboxes have the cipher 'GR' with the 'R' standing for Rex, which means 'King' in Latin.

Postboxes with the cipher of King Edward VIII are rare since he abdicated after reigning for only 326 days, and less than 200 postboxes with his cipher were manufactured.

Similarly, postboxes with George VI's ciphers are also scarce as he ruled for only 16 years, six of which were during World War II, and iron production during the war was diverted to other purposes, resulting in fewer postboxes being made.

In response to this information, someone wrote on Twitter:

"Posted many a card and letters in [postboxes] and lived around the corner [from one] over 60 years and didn't know that!"

"My youngest was absolutely fascinated by this and we've been spotting them," another added.

Nonetheless, not everyone is impressed, and there are those who say that they have been aware of this fact for some time.

One individual remarked: "Anyone who did not know this in their teens is obviously unaware of the world directly around them."

"Too much time on social media and not enough of [the] real world."

"If people don't know what those ciphers mean then they shouldn't be British," another comment stated.

It is worth noting that postboxes in Scotland do not feature the 'EIIR' cipher, as Scottish individuals did not acknowledge Queen Elizabeth as the second monarch with that name, since Queen Elizabeth I never ruled Scotland.