The British twenty pence (20p) coin - often pronounced "twenty pee" - is a unit of currency equaling twenty one-hundredths of a pound sterling.
Unlike the smaller denominations, the twenty pence coin was not introduced at decimalisation in 1970 but was added in 1982, with a design by William Gardner (showing a crowned Tudor rose). This original reverse design was changed to the current version featuring a segment of the Royal Shield by Matthew Dent in 2008; coins of the old design are still current and circulate together with the new ones.
To help identification and avoid confusion with similar sized coins the 20p is seven sided and like the 50p is an equilateral curve heptagon. The shape, with its constant rolling diameter, means that it is readily acceptable in vending machines. Its composition is 84% copper and 16% nickel.
Coins issued in 1990 have now been circulating for 29 years.
Twenty and fifty pence coins are legal tender only up to the sum of £10; this means that it is permissible to refuse payment of sums greater than this amount in 20p coins in order to settle a debt.