THE Great British postbox is like none other in the world.
The iconic red portals stand to attention on many street corners and hold our letters that get sent across the country.
But have you ever noticed the GR and ER symbols stamped on?
Well, they have an interesting meaning that not many people know about.
And the revelations have got Brits running to their nearest postboxes to see what theirs reads.
The letters on the front of postboxes have always had subtle reference Monarch of the time - which for 63 years was to Queen Elizabeth.
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And despite King Charles now taking the crown, the letters will remain the same.
The letters are called the “Royal Cypher” and they reveal when the post box was erected
If you find a postbox that has the letters “ER” on then you can usually tell it was produced within the past 70 years.
The Queen took to the throne in 1952 so a lot of post boxes will have been installed with these initials.
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They stand for Elizabeth, Regina which was the late monarch’s name followed by the word “Queen” in Latin.
Similarly, you can tell that a “GR” post box was put up during the era of King George V, from 1910 to 1936, while “GR VI” boxes were from the reign of George VI, from 1936 to 1952.
The G stands for George, and the R stands for Rex, which is King in Latin.
So if the post box in your area has these letters you know that it’s been standing proudly since before the 1950s.
Many royal fans recently learned the news and have said that their minds are blown.
One wrote on Facebook: “My youngest was absolutely fascinated by this and we've been out spotting them.
“We have a Victorian one that we are going to go visit.”
Another added: “Really interesting - thank you! I think this has to be the best post I have ever seen on here!”
Letterboxes have been in use since 1852, around 12 years after the first stamps entered circulation.
Red became the standard colour in 1874, although it would take a decade before they could fully repaint every existing box.
Why are post boxes being changed now King Charles III is on the throne?
Stamps and coins with the Queen’s image on are being replaced but post boxes are not.
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That’s because they’ve stood the test of time, despite monarchs coming and going throughout the years.
So unlike notes, coins or stamps, it doesn’t matter that King Charles has now taken over - the existing post boxes won’t be replaced.
Did you know post boxes were not always red?
The first post box is believed to have been installed in and around Paris in 1653.
The oldest example of a post box in Britain is said to be dated 1809 where it was installed in the wall of the Wakefield Post Office. It is now on display at the new Wakefield Museum.
Roadside wall boxes first appeared in 1857 as a cheaper alternative to pillar boxes, especially in rural districts across the country.
A year later, Richard Redgrave of the Department of Science and Art designed an ornate pillar box for use in London and other large cities.
In 1859 the design was improved, and this became the first National Standard pillar box.
But for early Victorian post boxes, green was adopted as the standard colour.
Between 1866 and 1879 the hexagonal Penfold post box became the standard design for pillar boxes.
During this time, the colour was then changed from green to red.
The first boxes to be painted red were in London in July 1874, although it would be nearly 10 years before all the boxes had been repainted.