Coin that looks like regular 20p but is actually really rare is set to sell for £700

The 25p coin, which is made from nickel brass, has a shield on one side and the Sovereign’s Orb on the other - it also features the words 'Experimental coin' and 'Royal Mint trial'

A rare 25p coin could be set to fetch up to £700 when it goes under auction today.

The coin looks exactly like a regular 20p - but it is actually a “trial piece” or otherwise known as a “pattern coin” that was released by Royal Mint before the 20p as we know it today was released into circulation in 1982. At the time, authorities had not decided whether the new coin would be worth 20p or 25p.

There are thought to be no more than 50 of these 25p coins in circulation - and unbelievably, this particular one had been handed out to one man in his spare change. The 25p coin, which is made from nickel brass, has a shield on one side and the Sovereign’s Orb on the other. It also features the words "Experimental coin" and "Royal Mint trial" printed on the coin.

It will now go under the hammer today at RWB Auctions where experts believe it could fetch between £500 and £700. YouTuber Christopher Collects, who works for RWB Auctions, said: “20p coins are a fixture in our change now, but the Royal Mint seems to have experimented with various ideas before they settled on the seven-sided coin we all recognise.

"Trial pieces would have been used to demonstrate the concept of a new coin to officials and may have been sent out to businesses that handle lots of cash to try out. This trial coin could easily be mistaken for a 20p, but we are certain it will sell for a lot more than that.”

It comes after postmistress Diane Bath, 62, who runs The Post Office in Broughton-in-Furness, Cumbria, spotted a new £1 King Charles coin that is entirely in one colour. All new £1 coins are made with two metal rings - the outside is made from nickel-brass, while the inside is nickel plated brass alloy.

But the rare £1 coin that Ms Bath found in a delivery of new coins delivered to her Post Office is entirely in brass. The coin features King Charles’ portrait on one side, while the other side depicts a new 2023 design of two bees to celebrate the monarch’s love of nature.

She now plans on selling the coin at auction. You should always be wary and do your research first before buying any coin on eBay, as there are always fakes floating around. Websites and Facebook groups from change experts like Coin Hunter can help you work out if a coin is the real deal or not.

You can also ask the Royal Mint to verify coins. If you're selling a coin, be aware that there isn't a guarantee for how much you could get on eBay unless you set a reserve price. Coins are really only worth what someone is willing to pay for them.