Error coin? 1918 penny any ideas? [solved]

Hi i have here a 1918 penny, i was sorting through a new lot of old pennies and came across this it seems very odd to me
you can make the outline of the king head on the other side of the coin, i was wondering if this an error where they stamped the one side to hard causing the shape to petrude out the other side? It looks like one side is less struck than the other side,

This "ghosting" effect is quite common in George V pennies. I have a few where it is quite extreme. I understand that it is caused by the dies clashing?

As an engineer its the only way i can see it happening, just found a few more in the lot of coins i got at a car boot sale, i like them they are quite cool. Cheers for the info buddy. :)

It was caused by the high relief of the Kings head, the absolute key date for these pennies is the 1926 ME (Modified Effigy) penny.

I have one that is in even worst shape. I have in my collection. It makes me think of Britannia by the sea, with a full moon behind her. Just love it.

Yes, very nice example of ghosting even though the coin is worn, it is still visible, apparently in Pennies this is quite common. Check here my Australian Pennies, with lower ghosting.

https://en.numista.com/forum/topic38730.html

I have a few British pennys with this as well, it's also common on Australian King George VI pennys.