Elusive black postboxes have captured the attention of Brits, with many having no idea why they're a special colour.

Traditionally, our iconic postboxes are painted a vivid red. There was a point in time when postboxes were green, but they were swapped to red in 1874 after complaints that the green boxes were too hard to see, especially in the countryside.

Not all postboxes are red, however. For a brief time throughout the 1930s, some boxes intended for airmail letters were blue, though these were retired in 1939. In 2012, several were painted gold to commemorate the gold medal winners at the London 2012 .

As for black ones? They represent an enigma wrapped in British postal heritage, sparking confusion among locals.

A recent discussion highlighted this curiosity when a user encountered a functioning black postbox nestled on a farm wall in Llanfydd, Wales.

They asked: "I came across this working postbox at the weekend. I've Googled it, and it says that it's either to celebrate Black History (for a regular pillar box) or to signify that it's out of use, but this one IS in use.

"It was on the wall of a farm, and I talked to the owner of said farm, and she didn't know either. Does anyone know more?"

Reddit users were quick to educate the original poster about the significance of black postboxes. These postboxes typically signal their retirement from service as letters are no longer collected. They are often found sealed and situated outside decommissioned post offices or in conservation areas.

However, the Reddit image displayed an unsealed black postbox, suggesting it may still be operational. But there was a simple explanation - the box was merely a replica.

As one observant commenter pointed out: "It's a replica postbox, not a real one. There's no Royal Mail branding on the collection card, nor a day token."

Accompanying their revelation was an Amazon link showcasing similar faux postboxes for sale.

The discussion progressed with several commenters expressing bewilderment that such dummy postboxes were allowed for purchase, considering they might mislead the public into actually using them.

To counter potential deception, someone noted: "I reported the selling site to the Post Office and Royal Mail, and they said it's not a copyright design, but they would take action if it were placed somewhere it may be thought to be real."

Another individual chimed in with their experience, remarking: "They're typically painted black when retired. I saw the one in Farnham station being painted over, as it, too, was embedded in the wall and couldn't be removed."

The original poster revisited the discussion to clarify their initial query, sharing: "I asked them if it was 'in use', she said yes. She may have said yes because it's a working postbox for the farm when I was asking if it's a working Royal Mail Collections Letterbox."

However, the colour black on a postbox does not necessarily signal it's out of service. In an emblematic move during 2020, four pillar postboxes across London, Glasgow, Cardiff, and Belfast turned black with majestic golden tops in celebration of Black History Month.

Each uniquely painted postbox commemorates a pivotal figure in the black British community and is adorned with a QR code. Upon scanning, the code reveals a list of eminent black Britons who have graced special postage stamps.