This made it easily distinguishable from round coins, both by feel and by sight, while its constant breadth allowed it to roll in vending machines. While this design may have been traditional, the shape of the new 50p coin, an equilateral curve heptagon, was revolutionary at time. The design on the reverse of the 50 pence coin features a symbol of Britannia that has appeared on UK coinage since 1672. In October 1969 the 50 pence coin joined the 5p (shilling) and 10p (florin) coins in circulation, leaving only the three copper coins – to be introduced on 15 February 1971 – to complete the new series of decimal coins. Royal Mint strike law face value commemorative coins We are back to the year 2011, the Royal Mint struck an early version of 50 pence swimmer coin that will become the “must have” in 50 pence coins collecting, because it became the rarest 50 pence coin, since 1969.