15 February 1971: Decimal Day – was the culmination of years of careful planning and centuries of debate about the introduction of decimal currency in Britain. As early as the 1690s, Sir Christopher Wren had advocated the introduction of ‘decimal coinage’, that is, coins and notes based around factors of 10, over the ancient system of pounds (£), shillings (s) and pence (d).

Until 1971, a pound was worth 240 pence and a shilling 12 pence, 1 penny was also then divided into two half pennies (ha’ pence) and four farthings. Among the other purse-breaking small change of old money, there were florins worth 2 shillings, half crowns, coins worth 2 shillings and 6 pence, six pence pieces and three penny (or thrupenny) bits.

The rate of a penny itself dated right back to the weight of silver at the time of the Norman Conquest. Indeed, one possible source of the English word ‘sterling’ as used in ‘pounds sterling’ is that some Norman pennies were supposedly stamped with a star as proof of their value.

In the eighteenth and nineteenth centuries, many countries, including Russia with the ruble, France with the franc and Spain with peseta, converted to decimal forms of currency. While the matter was the subject of parliamentary debates and commissions in 1850s and 1860s and prototype decimal coins were even minted, Britain appeared reluctant to give up time-honoured notes and coins that were familiar throughout the Empire.

In the Victorian period, perhaps the most famous advocate of a decimalisation remained a creation of the novelist Anthony Trollope. The aristocratic parliamentarian Plantagenet Palliser, Duke of Omnium, one the main characters in Trollope’s ‘Pallister’ sequence of novels, is a firm believer in, and something of a bore about, the merits of decimal currency. But it was close to forty years after the final Pallister novel was published before the issue was considered seriously again. In 1918, George V set up a Royal Commission to look into decimal currency, but they too appeared unwilling to recommend changing the coins of the realm.

A man would be in space before, finally, the British government, on the verge of applying to join the European Common Market for the first time, accepted the idea in 1961. By then the old money was judged a barrier to international trade by Macmillan’s Conservative administration and, as a ‘practical business decision’, a Committee of Inquiry chaired by the Earl of Halsbury was tasked with considering how country could move to a decimal currency. One of the wilder ideas subsequently floated by treasury wonks was the abolition of the pound and its replacement with a new 100 pence note to be called ‘The Royal.’ In the event, the pound survived but was pegged to a 100 new pence and backed up by new five, ten, twenty and fifty pound notes and a range of shiny new fifty, ten, five, two, one and half pence pieces. The official announcement of the changeover was made by the Chancellor of the Exchequer, James Callaghan, on 1 March 1966, with the new notes and coins to be launched five years from then.

Alongside a government guide and promotional films and television adverts intended to help people get to grips with the nation’s newfangled currency in 1971, there was a pop single, entitled ‘Decimalisation’, written by Gordon Rees and Ernie Ponticelli and sung by every Granny’s favourite, Max Bygraves.

Despite the official backing of the Decimal Board and Bygraves crooning such winning lines as ’Gone are the days when twelve old pence added up to make a shilling, not much sense’ and ‘The half crown too has gone for good - a coin that foreigners never understood’, the record failed to make the top forty, still less dislodge George Harrison’s ‘My Sweet Lord’from that week’s top slot.