WE'VE all used a postbox before - the iconic red portals to get our letters sent across the country.
And it turns out, the GR and ER symbols stamped on them have interesting meanings.
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 the last 63 years was to Queen Elizabeth.
And even though it's now her son King Charles in charge, it's going to stay that way.
The letters are called the “Royal Cypher” and they give any eagle-eyed onlookers a subtle clue as to when the post box was erected.
READ MORE ON THE KING CHARLES
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.
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.
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The G stands for George, and the R stands for Rex, which is King in Latin.
So if the post box in your village sports these letters you know that it’s been standing proudly since before the 1950s.
Royal fans who have just learned of the news 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.
But what will happen now King Charles III is on the throne?
Now the Queen has passed, stamps and coins with her image are being replaced - but the same can't be said for post boxes.
Read more on The Sun
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.
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