British One Penny coin

The coin was initially minted from bronze, but since 1992 it has been minted in copper-plated steel. As this is less dense than bronze, post-1992 coins have been to some amount thicker. The British decimal Penny (1p) coin, fashioned by the Royal Mint, was issued on 15 February 1971, the day the British money was decimalised. In practice, it had been existing from banks in bags of £1 for some weeks previously. The coin weighs 3.56 grams and has a diameter of 20.32 millimetres.
The reverse of the coin, intended by Christopher Ironside, is a crowned portcullis with chains (an adaptation of the Badge of Henry VII which is now the brooch of the Palace of Westminster), with the numeral "1" written below the portcullis, and either NEW PENNY (1971–1981) or ONE PENNY (1982–present) above the portcullis.
During the times gone by of the coin, three unlike obverses have been used so far. Between 1971 and 1984 the head of Queen Elizabeth II by Arnold Machin was used, in which the Queen wears the 'Girls of Great Britain and Ireland' Tiara.