his crown coin was issued to celebrate the eightieth birthday of Queen Elizabeth The Queen Mother (the mother of Queen Elizabeth II) on 4th August 1980.
At the time of decimalisation in 1971, the United Kingdom Crown coin (equal to 5 shillings) was redenominated as a 25p coin and pieces struck prior to 1990 – all the way back to 1818 – continue to be legal tender for that amount. The old denomination had been a regular circulating coin in the 19th century, but in the 20th century it became more of a commemorative denomination.
The Royal Mint continued issuing commemorative coins in the same format – using the traditional coin dimensions, but in copper-nickel just as the last pre-decimal crowns had been, also denominated as 25 pence.
Although not circulating, these coins are legal tender for 25 pence, but contrary to popular belief this does not mean that banks and retailers automatically have to accept them. In the United Kingdom, they are accepted by Royal Mail post offices.