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. These were initially also denominated as 25 pence but the "Crown" was changed in 1990 to a commemorative £5 (five pound) coin, having the same dimensions and weight but with a face value twenty times as great.
The denomination is used to mark special occasions, usually royal in theme, rather than for use in general circulation. Although not circulating, these coins are legal tender.
This commemorative £5 Crown-sized coin was issued as a Christmas gift.
The Royal Mint says:
"This year, give a Christmas card that your loved ones will want to keep forever. The Royal Mint’s 2018 Christmas coin celebrates a story entrenched within our Christmas traditions - The Nutcracker. The coin is the shimmering centrepiece of this magical Christmas card.
Nutcrackers carry with them a sense of tradition as well as an abundance of stories and legends of the past. Just like The Nutcracker story, the tradition of coins at Christmas has a very long history, with St Nicholas placing coins in stockings drying on the chimney ledge; Christmas and coins go hand-in-hand.
Keep the spirit of the season alive by gifting this year-dated £5 Nutcracker coin. Artist Harry Brockway has captured the magic and spirit of The Nutcracker through the snowflakes, Sugar Plum Fairy and of course, the Nutcracker Soldier - the centrepiece of The Nutcracker story."
The coins come in a presentation folder, Royal Mint Product Code: UK18CNBU, issue price: £13.00. | 
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