“NOTE FOR YOUNG PEOPLE AND AMERICANS: One shilling = Five Pee. It helps to understand the antique finances of the Witchfinder Army if you know the original British monetary system: Two farthings = One Ha'penny. Two ha'pennies = One Penny. Three pennies = A Thrupenny Bit. Two Thrupences = A Sixpence. Two Sixpences = One Shilling, or Bob. Two Bob = A Florin. One Florin and One Sixpence = Half a Crown. Four Half Crowns = Ten Bob Note. Two Ten Bob Notes = One Pound (or 240 pennies). Once Pound and One Shilling = One Guinea. The British resisted decimalized currency for a long time because they thought it was too complicated.”

Staff and customers in Sainsbury's, 24/25 Drury Lane, London, on the day decimal currency was introduced in 1971. From the Sainsbury Archive.

How many in the picture can you name?

British penny. This replaced the old, much bigger, penny in 1971.

The government effected change on a scale that could have altered the fabric of society and caused major economic and political problems. Instead, they took their time, thought things through, and brought in experts. [...] Fifty years on, it’s hard not to wonder where it all went wrong.