<P> By the end of George V's reign the threepence had become unpopular in England because of its small size (George Orwell comments on this in Keep the Aspidistra Flying), but it remained popular in Scotland . It was consequently decided to introduce a more substantial threepenny coin which would have a more convenient weight / value ratio than the silver coinage . The silver threepence continued to be minted, as there may have been some uncertainty about how well the new coin would be accepted . The Edward VIII era saw the planned introduction of a new, larger, nickel - brass (79% copper, 20% zinc, 1% nickel) twelve - sided threepence coin . This coin weighed 6.6 grams and the diameter was 21 mm across the sides and 22 mm across the corners . The obverse shows a left - facing effigy of the king (not right as would have been the convention to alternate the direction) with the inscription EDWARDVS VIII DG BR OMN REX FD IND IMP, and the reverse shows a three - headed thrift plant with the inscription THREE PENCE 1937 . A total of just 12 of these coins were struck for experimental purposes and sent to a slot machine manufacturing company for testing . The whereabouts of six of those 12 are known . However, the other six are still out there somewhere and, as such, they are extremely rare today . An example was sold at auction in 2013 for £ 30,000 There are two types of Edward VIII brass threepences . The first type has the date broken by a thrift plant design and the second has the date below . </P> <P> During the reign of King George VI, circulation silver threepences were produced only in 1937--45 (and almost all the 1945 examples were subsequently melted down). The obverse shows a left - facing effigy of the king with the inscription GEORGIVS VI DG BR OMN REX, while the reverse has an elegant design of a shield of St George lying on a Tudor rose, dividing the date, with the inscription FID DEF IND IMP THREE PENCE . The nickel - brass threepence took over the bulk of the production of the denomination, being produced in all years between 1937 and 1952 except 1947 . Apart from the king's head and name, and the weight being increased to 6.8 grams, the coin was identical to that prepared for Edward VIII . Coins dated 1946 and 1949 were minted in far fewer numbers than the rest, and as nickel - brass wears very quickly, higher grade specimens of these coins are expensive to buy now (both over £ 500 for uncirculated examples). The scarce dates are 1948, 1950 and 1951 and these are now selling for £ 60--£ 80 in mint state . </P> <P> The physical dimensions of the brass threepence remained the same in the reign of Queen Elizabeth II . The effigy of the queen produced by Mary Gillick was used, with the inscription ELIZABETH II DEI GRA BRITT OMN REGINA FD used in 1953, and ELIZABETH II DEI GRATIA REGINA FD used in all other years . The reverse shows a Tudor portcullis with chains and a coronet, with the inscription THREE PENCE date . This coin was produced in all years from 1953 to 1967, and in 1970 (in proof sets only). </P> <P> Following decimalisation, the brass threepence ceased to be legal tender after 31 August 1971 . </P>

When did threepenny bits go out of circulation