The undated 20p coin
In November 2008 a number of 20p coins were incorrectly minted, resulting in the coins being undated.
This problem affected less than 250,000 coins of the 136 million 20p pieces minted in 2008-09 and was due to the previous obverse (the ‘Heads’ side) being used with the new reverse (the ‘Tails’ side) design, meaning the year of issue did not feature at all.
These coins remain legal tender and still have a face value of 20p.
Check the images below to see the difference between the correct 20p coin and the undated 20p coin.