The old bronze penny was slated for elimination as decimal currency was planned in the 1960s. It continued to be struck after 1967, still bearing that date. The 97 percent copper, 0.5 percent tin, 2.5 percent zinc alloy was used again for the 1960s pennies. Finally, there was an issue of proof quality coins dated 1970 for collectors, to bid farewell to a denomination which had served the country well for 1200 years. The longstanding depiction of Britannia on the penny was translated by sculptor Christopher Ironside to the post-decimal fifty-pence coin.