Decimal coins

(England Twitter)-1968: The first decimal coins were introduced. These were cupro-nickel 5p and 10p coins which were equivalent to and circulated alongside the 1/- and 2/- coins.
1969: The curved equilateral heptagonal cupro-nickel 50p coin replaced the 10/- note.
1971: The decimal coinage was completed when decimalisation came into effect in 1971 with the introduction of the bronze ½p, 1p and 2p coins and the withdrawal of the 1d and 3d coins.
1980: Withdrawal of 6d coins, which had circulated at a value of 2½p.
1982: The word "new" was dropped from the coinage and a 20p coin was introduced.
1983: A £1 coin was introduced.
1983: The ½p coin was last produced.
1984: The ½p coin was demonetised
1990s: The 5p, 10p and 50p coins became smaller.
1991: The old 1/- coins, which had continued to circulate with a value of 5p, were demonetised in 1991 after the 5p coin became smaller.
1992: Bronze was replaced with copper-plated steel
1993: The 2/- coins were similarly demonetised.
1998: The bi-metallic £2 coin was introduced.
2007: By now the value of copper in the pre-1992 1p/2p coins (which are 97% copper) exceeded the value to such an extent that melting down the coins by entrepreneurs was becoming worthwhile (with a premium of up to 11%, with smelting costs reducing this to around 4%)—although this is illegal, and the market value of copper has subsequently fallen dramatically from these earlier peaks.
At present, the oldest circulating coins in the U.K. are the 1p and 2p copper coins introduced in 1971. Before decimalisation, change could contain coins aged one hundred years or more, with any of five monarchs' heads on the obverse.
In April 2008 an extensive redesign of the coinage was unveiled. The new designs were issued gradually into circulation, starting in summer 2008. The new reverses of the 1p, 2p, 5p, 10p, 20p and 50p coins feature parts of the Royal Shield, and the new pound coin depicts the whole shield. The coins are of the same specifications as those with the old designs (which will continue to circulate).