with the inscription BRITANNIA. After the mint moved from the Tower of London to Tower Hill the production of gold and silver coins took precedence over copper. The production of copper coins did not resume until the reign of King George IV (1820–1830), when farthings were produced in 1821. The issue of new halfpennies did not happen until 14 November 1825 as a result of a disagreement between the egocentric designer Benedetto Pistrucci and the authorities, which resulted in William Wyon being invited to design the coins instead. This delay may be regarded as a good thing, as Wyon's designs are generally considered among the most elegant British coins. The George IV halfpenny was produced between 1825 and 1827, weighed 9.1–9.5 grams, with a diameter of 28 millimetres. The obverse shows a left-facing laureated bust of King George IV with the inscription GEORGIUS IV DEI GRATIA date, while the reverse shows a right-facing seated helmeted Britannia with a shield and trident, with the inscription BRITANNIAR REX FID DEF. Wyon's preference was to put the date under the king's bust, and to put the rose, thistle, and shamrock in the exergue underneath Britannia where the date commonly appeared before. The halfpenny of King William IV (1830–1837), produced in 1831, 1834, and 1837, continues the George IV design but with a right-facing bust of the new king, with the inscription GULIELMUS IIII DEI GRATIA date, while the reverse is identical to the previous reigns'. The halfpennies of Queen Victoria's long reign (1837–1901) can be basically divided into the copper issue of 1838–1860, where the coins were 9.1–9.5 grams in weight and 28 millimetres in diameter, and which were very similar to the halfpennies of her two predecessors (with the obvious substitution of REG for REX on the reverse), and the bronze issue of 1860–1901 (which itself is split between 1894 and 1895 into coins displaying the "young head" and the "old head" of the Queen). The bronze coins weighed 5.5–5.8 grams and were 25 millimetres in diameter. The bronze coins also featured the denomination HALF PENNY on the reverse for the first time, with the date in the exergue beneath Britannia. The inscription on the obverse of the "young head" coins reads VICTORIA D G BRITT REG F D, while on the "old head" it is VICTORIA DEI GRA BRITT REGINA FID DEF IND IMP. Some 1874–1876 and 1881–1882 halfpennies have an