HAVE you checked your loose change today? It could be worth more than you think. 

The Royal Mint has today encouraged people to rifle through their change to discover whether an "incredibly rare" 50 pence piece is hiding in their wallet, a jam jar or down the back of a sofa.

Around one in 300 people is estimated by the Mint to have the Kew Gardens coin in their possession after it was released into circulation in 2009 to mark the 250th anniversary of the Royal Botanic Gardens.

The Mint described the coins as "incredibly rare", so much so that it is the rarest commemorative coin design to be placed into general UK circulation, with only 210,000 of them ever released.

This compares with 22.7 million 50 pence coins produced with the shield of the Royal Arms design in 2008 and 7.5 million 50 pences released in 2010 to celebrate Girlguiding.

Around 28.9 billion UK coins generally are estimated to be in circulation.

The Kew Gardens coin, which features a design showing the pagoda of the Gardens encircled by a twisting vine plant, is already prized by collectors and a search on the eBay auction website showed that several have recently sold for upwards of £20.

A spokeswoman at the Royal Mint said that while the face value of the coin is 50 pence, "what it is worth to collectors is another matter".