On 1 March 1966 the Chancellor of the Exchequer, James Callaghan, announced that the centuries-old system of 12 pennies to the shilling and 20 shillings to the pound would be replaced by a decimal currency system in which the pound was to be divided into 100 units. Recognising the enormity of a change that would affect every business and household in the country, the government proposed a five-year preparatory period before the official changeover.

In order to handle the vast production of hundreds of millions of new decimal coins a purpose-built Royal Mint at Llantrisant in South Wales was opened by the Queen in December 1968. A system of currency that had survived for more than 1,000 years had been replaced without any major controversy. The United Kingdom had finally become a decimal country.

Since 1968 there have been many changes to the coinage with new denominations, new sizes and new alloys, but the core reverse designs of the decimal series by Christopher Ironside have remained intact for 40 years. It is indeed one of the longest surviving series in the history of British coinage.