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 is part of an 18-coin collection issued by the Royal Mint for the London 2012 Summer Olympics.
The 2012 Summer Olympics, formally the Games of the XXX Olympiad and commonly known as London 2012, took place in London and to a lesser extent across the United Kingdom from 25 July to 12 August 2012.
A Celebration of Britain is a collection consisting of 18 Crown-sized coins denominated as £5 which were released one at a time, every 28 days - so that the first six are dated 2009 and the last twelve are dated 2010. All feature the London 2012 logo, which is colourised on the reverse. The coins are grouped around three themes, with six coins dedicated to Mind, Body and Spirit respectively, and each theme having a differently coloured logo.
The Musical Instruments coin is part of the Spirit of Britain series and features Cornelia Parker' sculpture "Breathless". This coin celebrates British popular music which originated in the sixteenth and seventeenth centuries with the arrival of the broadside ballad. Then came the brass bands, followed by music halls and dance bands. In the early 1960's The Beatles arrived and set the standard for popular music.
"Breathless" is a work commissioned specially from the British artist Cornelia Parker for display in the new British Galleries. It was specifically designed to fill the oculus or open space newly created between the two floors of the Galleries in a corner. It is made of 54 defunct brass band instruments which have been squashed flat and hung from wires. They are designed to be seen from both above and below, with polished upper surfaces and tarnished undersides. The work is an attempt by the artist to explore such ideas of duality as silence/noise, upper class/lower class, and death/resurrection.
The inscription quotes John Lennon and Paul McCartney's song "All you need is love". | 
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