The Royal Mint has revealed the UK's rarest coin in general circulation: the Kew Gardens 50p, released in 2009.
The coin was released to celebrate the 250th anniversary of the Royal Botanic Gardens - but only 210,000 ever made it into circulation. While this might seem like a lot, it's a tiny number compared with, say, the 22.7 million 50 pence pieces doing the rounds bearing the 2008 shield of the Royal Arms design.
As a result, says the Royal Mint, the Kew 50p is so rare that only one in every 300 people in the UK is likely to have it in their change.
"Whilst we're urging everyone to check their change to see whether they could have one of these exceptional coins in their pockets, we also want to encourage the nation to look more closely at all of the coins we use every day," says Shane Bissett, director of commemorative coin at The Royal Mint.
"They really are miniature works of art worth looking out for, admiring and collecting – and keeping hold of them is a great way for us to build our own private art galleries."
For those checking their pockets now, the Kew coin carries a design by Christopher Le Brun, based on the Kew pagoda encircled by a vine. It carries the dates '1759' and '2009', and has the word 'KEW' at the base of the pagoda.
Unfortunately, if you haven't got one in your purse today, the chances of finding one are set to decrease, now that the coin's been highlighted as the UK's rarest. "Now that people know just how rare this particular coin is, we expect them to disappear from circulation fast," says Bissett.