OTL February 1971: the British Pound was decimalised and 100 new pence replaced the 240 old pennies, and with it, the shilling was no more.
The LSD, or pounds, shillings and pence system was an arcane system whose days had gone: it was time for Britain to join the rest of the world with a decimalised currency.
ATL February, 1971: the British Pound was replaced by the New Pound, worth five old pounds and divided into 100 shillings. The old pennies were kept for an interim period, being still 12 to the shilling, but the high inflation on the 1970's soon saw their demise, leaving the decimalised pound worth a lot less than the one it replaced.
The shilling coins in use were retained as they now formed the units of the new pound: the shilling piece became the 'cent' of the new pound; the florin, or two shilling piece (which itself was introduced 200 years in an earlier attempt to decimalise the currency) was also kept, as was the half-crown, now used as a two-and-a-half shilling coin.
The crown was reintroduced as this had a value of five shillings, which was a useful addition to the 1,2 and 2 1/2 coins.
A double crown, or ten-bob piece was created, initially in circulation alongside its equivalent note of ten shillings.
The old pound note too was kept in use, and alongside it too was the 20 shilling coin, or quid. This caused confusion, particularly amongst the elderly, as a quid used to mean a pound, and was not intended to be used to describe the new pound. The government rsponded with Public Information films and newspaper articles, but it took the character Ena Sharples on television's longest running soap, Coronation Street to get the message across when she said Ay duck, a pound's five quid now, ya know.
As inflation took hold, the ten shilling and old pound note ceased to be available and the old pennies disappeared as well. New coins were needed and a 50 shilling coin was introduced, sometimes referred to as ten crowns.
Thirty odd years after decimalistion, the fact that there was once 12 pennies to a shilling had been forgotten and people worried more about the sixty shilling pint of beer and the twenty shilling litre of petrol, and shuddered at adopting the euro, at ten to the pound.