Could your rare 50p coin be worth 1,000 times its face value?
The rarest pieces can fetch up to £500 at auction
The 50 pence piece depicting Kew Gardens has been named the most coveted coin of its kind in circulation and could fetch more than 1,000 times its face value, the Daily Telegraph reports.
The coin, which features Kew's Japanese pagoda, has maintained its position at the top of Change Checker's scarcity index, with a rating of 100. It was minted in 2009 to celebrate the botanic garden's 250th anniversary.
Just 210,000 examples were made, making it the rarest British coin in general circulation. According to eBay it has previously sold for as much as £510, the Telegraph says, so those hoping for a jackpot should check their piggybank.
There are 53 other editions of 50p in circulation. While most won't earn you any more than their face value, others could still fetch a pretty penny.
At the number 2 spot is the Football 50p, minted for the 2012 Olympics. It has a scarcity index of 78 and has fetched up to £20 on eBay, the Daily Telegraph says. It's followed by triathlon, judo and wrestling at 76, 74 and 73 respectively.
Change Checker doesn't just take into account the mintage figures, but also the latest ownership information as recorded by its users, as well as the number of times someone has requested the coin as a swap over the previous three months – an indication of collector demand.
"The Scarcity Index does not necessarily equate to value but it is certainly an effective indicator," the website says.
Jemima Puddle-Duck comes in at number 8 with a ranking of 58, making it the most popular Beatrix Potter coin. It's above Squirrel Nutkin, whose coin has a scarcity factor of 28, and Beatrix Potter herself, who attracts a rating of just 5.
New to the list is Isaac Newton, who was given a limited release last month. He debuts with a scarcity value of 23. Other less valuable designs include tributes to the NHS, the dictionary, the girl guides, Roger Bannister and the Victoria Cross.
The 50p, made of three parts copper to one part nickel, was first issued in 1969 with what the Royal Mint describes as a "revolutionary" design of an "equilateral curve heptagon”, marking it out from the other round denominations. The original design was larger and heavier.
On Change Checker's other indices, the 2002 England Commonwealth Games £2 coin jumped two places to number one for its denomination, and a scarcity factor of 100, thanks to extra swap interest.