The United Kingdom 1p coin was one of three new coins introduced into general circulation on the 15 February 1971 when the United Kingdom adopted a new decimal currency system. The other two new coins were the 1/2p and 2p coins (5p, 10p and 50p had been introduced earlier).
The one penny coin is currently the lowest circulating denomination of the British (decimal) Pound Sterling, after the half penny was demonetised in 1984.
Between 1971 and 1991, one penny coins were made of bronze. The first copper-plated steel 1p coins were struck in 1992. The reason for this change was the increase in the price of metals on the world markets. The coins have a mild steel core and are electroplated with copper - consequently they are magnetic. They retained the original design by Christopher Ironside until the introduction of the new 1p by Matthew Dent in 2008.
Coins of this type are still current and circulate in parallel with the new ones. Coins issued in 1998 have now been circulating for 20 years.
One penny and two pence coins are legal tender only up to the sum of 20p; this means that it is permissible to refuse payment of sums greater than this amount in 1p and 2p coins in order to settle a debt.