From rummaging through the back of the sofa to asking for extra change at your local shop, County Durham residents might strike gold – or at least silver – if they find this rare undated 20p coin.

The error coin was only in circulation for a very short time and the Royal Mint is "unable to comment on the value of any ...

This led the Reality Check team to wonder if it is in fact the least valuable British ... smallest coin was the farthing, which was a quarter of a penny. At the time there were 240 pence to ...