The British decimal Half Penny (1/2p) coin was issued on 15 February 1971, the day the British currency was decimalised. In practice it had been available from banks in bags for some weeks previously.
The coin was minted in bronze. The coin weighed 1.78 grams and had a diameter of 17.14 millimetres. It was the smallest coin used in the decimal currency coinage by both size and value, and was nicknamed the "tiddler" on account of its size. By the early 1980s its value was minimal and its main utility was as a useful screwdriver of small screws. The 1984 half penny was only issued in proof sets by the Royal Mint, and the coin was demonetised and withdrawn from circulation in December 1984.
The reverse of the coin, designed by Christopher Ironside, was simply a crown, with the numeral "1/2" below the crown, and either NEW PENNY (1971-1981) or HALF PENNY (1982-1984) above the crown.
During the existence of the coin, only one obverse was used -- the head of Queen Elizabeth II by Arnold Machin, with the inscription ELIZABETH II D.G.REG.F.D. date.