The half ounce silver piece is a bullion and commemorative denomination issued by the Royal Mint. It is used mostly for Britannia-type coins: British bullion coins issued in gold since 1987 and in silver since 1997. The original Britannia silver coins contain one troy ounce (1 oz) of silver and have a face value of £2.
Silver Britannias are also issued in fractional sizes of one-half, one-quarter, one-tenth, 1/20th and 1/40th of a troy ounce and with face values of £1, 50p, 20p, 10p and 5p respectively (that is, the half ounce silver piece is officially denominated as £1). There is also a five-ounce coin of face value £10.
The designs have a "definitive" version issued every year as "bullion-grade" (Brilliant Uncirculated coins), as well as one-year types issued as proofs only. Some of the one-year types are not Britannia-themed. | 
