Everyone is being encouraged to check their change for an “extra-special” 50p coin that tops the Royal Mint’s list of its rarest coins.

You could be sitting on a fortune you didn’t even know about, as the Royal Mint revealed its rarest 50p coins currently in circulation.

Since moving to pounds and pence in 1971, more than 70 variations of the 50p coin have been minted, including several rare designs which could be worth a lot more than 50p.

One highlighted by the Royal Mint as being “extra-special” is the first design of the 2011 Olympic Games aquatics 50p sure to “get collectors excited”.

Somerset County Gazette: The “extra-special” 2011 Olympic Games aquatics 50p coinThe “extra-special” 2011 Olympic Games aquatics 50p coin (Image: Royal Mint)

They explained: “The design was created by Jonathan Olliffe, and it depicts a swimmer in action with fluid lines struck into the metal representing the waves.

“In the rare first design, these lines covered the swimmer’s face. Soon after its release, the coin was tweaked to make the face more visible, but not before the first design made it out into the world.

“One of the most exciting aspects of this special 50p is that no one knows exactly how many entered circulation before the changes were made, only that numbers are extremely limited.

“This is often the case with error coins, and they immediately become a collectable piece. Few have ever been sold and many take pride of place in private collections, but there’s always a chance this valuable coin could find its way to you.”

Other rare coins in include The famous Kew Gardens 50p remains the most coveted coin in circulation, with a mintage of just 210,000, the Mint said.

What makes a coin valuable?

The 50 pence piece has become the most valued and collected coin in the UK, with many collectable designs appearing on its heptagonal canvas.

Its 27.5mm diameter makes it the largest of any British coin, and allows space for decorative pictures. It has often been used to celebrate big events over the past 50 years of British history.

The rarest coins tend to be of the greatest value, with the mintage (number of coins with each design made) being the fundamental attraction for collectors.

Along with the design, other aspects of the coin which increase value are the condition of the coin and whether it has an error in its design.

The way in which it is sold can also determine the coin’s value - while some coin collectors will bid vast amounts of money on ebay or at auction, others opt for more robust valuations by selling via a coin dealer.

Top 10 most valuable 50p coins, according to Royal Mint

Here is a list of the top 10 most valuable coins, when they were made and how many were minted:

  1. Olympic Aquatics (2011), unknown
  2. Kew Gardens (2009), 210,000
  3. Olympic Wrestling (2011), 1,129,500
  4. Olympic Football (2011), 1,161,500
  5. Olympic Judo (2011), 1,161,500
  6. Olympic Triathlon (2011), 1,163,500
  7. Peter Rabbit (2018), 1,400,000
  8. Flopsy Bunny (2018), 1,400,000
  9. Olympic Tennis (2011), 1,454,000
  10. Olympic Goalball (2011), 1,615,500