Rare 50p coin sells for 300 times its value after Royal Mint error – do you have one down the back of your sofa?

CHECK down the back of your sofa for a rare 50p coin which sells for 300 times its value after a Royal Mint error.

The 50p Kew Gardens coin features the Chinese Pagoda at the famous London landmark of the same name.

Kew Gardens is famous for its stunning green spaces and scenery.

Back in 2009, a 50p coin was released into circulation that recognised the British landmark.

The Royal Mint launched the coin to mark 250 years since the botanical gardens opened.

It features the site's iconic Chinese Pagoda and displays the years 1759 and 2009.

Only 210,000 of these coins were released, making it pretty rare.

And one of the 50p coins attracted 36 bids on eBay on Thursday before selling for £141.

How to check if your small change is worth anything

Online tools from change experts like  are helpful to see how much it could be worth as well and you can also refer to Change Checker's latest scarcity index update to see which coins are topping the charts.

Change Checker tracks which rare coins and valuable notes are worth the most.

You can check how much the coin is selling for on eBay, by searching the full name of the coin, selecting the "sold" listing and then toggling the search to "highest value".

It will give you a rough idea of the amount that coin is selling for.

But remember, coins are only really worth what someone is willing to pay for them.

Sometimes collectors might fork out more if they're desperate to finish a set.

Other times, you might get significantly less for the same coin.

Special 50p coins aren't the only big wins you could find in your piggy bank, we've listed the rarest 10ps here.

And, here is a round-up of all the most valuable coins in Britain.