The British pre-decimal penny coin, abbreviated as 1d (from "denarius" - the Roman coin from which the penny is directly descended), was a unit of currency that equalled one two-hundred-and-fortieth of a pound sterling (there were 20 shillings to a pound, and 12 pence to a shilling so one pound was equal to 240 pence).
The denomination continues the tradition of earlier penny coins of Great Britain, which also featured the figure of Britannia. In 1801 the parliaments of Great Britain and the Kingdom of Ireland each passed an Act of Union, uniting the two kingdoms and creating the United Kingdom of Great Britain and Ireland. Re-coinage followed in 1806; there was a short-lived penny format with larger coins with concave surfaces struck by the Soho Mint but it was only issued for two years.
After 1807, no penny coins were issued until 1825 (with the exception of some circulating silver pennies), when this smaller version with a new-look Britannia and traditional flat surfaces was introduced; the design is by William Wyon, chief engraver of the Royal Mint, which was the only mint issuing the new coins.
The design is identical to that of the half penny, farthing and half farthing coins minted in the same years; the difference is only in size. Typically for British coinage of the time, the denomination (or, indeed, the country of issue) is not spelled out on the coin.
All these pennies were minted in copper, but after 1860 the denomination changed to bronze with an even smaller size.
One penny coins issued in 1858 circulated for 12 years until all British copper coinage was demonetised after 31 December 1869.
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