For the pre-decimal halfpenny coin see
British halfpenny coin. The
British decimal half penny (½p) – (pronounced as HAYP-nee,
IPA: ) and also written halfpenny or ha'penny – was first 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 decimal half penny, worth 1.2 pre-decimal pence, enabled the prices of some low-value items to be more accurately translated to the new decimal currency. It also allowed the pre-decimal
sixpence to remain in circulation (with a value of 2½ new pence) alongside the new decimal coinage. In the same vein, a decimal quarter-penny coin (to be struck in
aluminium) was also proposed (which would have allowed the pre-decimal
threepence to continue to circulate with a value of 1.25 new pence), but ended up never being produced.
See more at Wikipedia.org...