The British pre-decimal penny was a denomination of sterling coinage worth 1⁄240 of one pound or 1⁄12 of one shilling.
Before Decimal Day in 1971, sterling used the Carolingian monetary system (£sd), under which the largest unit was a pound (£) divisible into 20 shillings (s), each of 12 pence (d).
[2] The design and specifications of the sterling penny were unchanged by unification, and it continued to be minted in silver after 1707.
However, by George III's reign there was a shortage of pennies such that a great many merchants and mining companies issued their own copper tokens e.g. the Parys Mining Company on Anglesey issued huge numbers of tokens (although their acceptability was strictly limited).
[4] In 1797, the government authorised Matthew Boulton to strike copper pennies and twopences at his Soho Mint in Birmingham.
[5] In 1857 a survey by the Royal Mint found that around one third of all copper coinage was worn or mutilated, often by advertisements.
[8] The specifications of the bronze version of the penny were a mass of 9.45 g (0.333 oz) and a diameter of 30.86 mm (1.215 in),[9] and remained as such for over a hundred years.
George V pennies were produced every year to the same standard until 1922, but after a three-year gap in production the alloy composition was changed to 95.5% copper, 3% tin and 1.5% zinc, although the weight and size remained unchanged (which was necessary because of the existence by then of large numbers of coin-operated amusement machines and public telephones).
Finally, there was an issue of proof quality coins dated 1970 produced to bid farewell to the denomination.