Coins of the pound sterling coins' designs. As of 31 March 2016, there were an estimated 30.14 billion coins circulating in the United Kingdom. The first decimal coins were circulated in 1968. These were the five pence (5p) and ten pence (10p), and had values of one shilling (1/-) and two shillings (2/-), respectively, under the pre-decimal £sd system. The decimal coins are minted in copper-plated steel (previously bronze), nickel-plated steel, cupronickel and nickel-brass. The two-pound coins, and, as from 28 March 2017 the new one-pound coins, are bimetallic. The coins are discs, except for the twenty pence and fifty pence pieces, both of which
Manx pound and there is no guarantee of convertibility beyond that given by the Manx authorities. However, the requirement in the island's Currency Act 1992 for the Isle of Man Treasury to exchange Manx Pound banknotes on demand for Bank of England notes in practice restricts the issue of unbacked currency, and the aggregate total of notes issued must be pre-approved by Tynwald. ISO 4217 does not include a separate currency code for the Manx pound, but where code distinct from GBP is desired, "IMP" is generally used. UK notes and coins (whether from banks in England, Scotland, or Northern Ireland) are