Christopher Ironside 50p (2013)

The Ironside 50p went into general circulation in large numbers, so a worn coin from change carries only a small premium, and one with crisp detail in the lion's mane and the unicorn's horn is worth more than a flattened one. The gap between circulated and brilliant uncirculated is unusually wide for this design, because the 2013 presentation pack was sold in small numbers and sealed packs are keenly collected. The coin from the 2013 annual set and the proof and silver strikes are valued as separate collector pieces.

With 7,000,000 struck for circulation, the Christopher Ironside 50p is the 56th rarest of the 81 ranked 50p designs and has the 124th lowest mintage of all 194 circulating UK designs. That puts it in the Uncommon band, for mintages 2,500,000 to 9,999,999.

The next rarer 50p is the Beatrix Potter 50p, with 6,900,000 struck, and the next more common is the Girlguiding 50p, with 7,410,090 struck.

Look for a whole coat of arms: a crowned shield held up by a lion on the left and a unicorn on the right, with FIFTY PENCE around the top and a large 50 underneath. It is easy to mix up with the Royal Shield 50p from 2008, but that coin shows only the lower part of the shield and has no animals beside it. The year 2013 is on the heads side, next to the Queen's fourth portrait. Ironside's arms design has no recorded varieties or errors.

Christopher Ironside drew the reverses for the first decimal coins, and in 2013 The Royal Mint marked the hundredth anniversary of his birth by going back to his own drawings. In the 1960s competition for the new 50p, which appeared in 1969, he put forward a Royal Arms design alongside the seated Britannia that won. The Royal Arms design was set aside and stayed unissued for more than four decades until this coin. The design is the full coat of arms rather than the shield alone. A crowned shield sits in the centre, its quarters showing the three lions, the lion rampant and the harp, with a crowned lion supporting it on the left and a unicorn on the right. The mottoes HONI SOIT QUI MAL Y PENSE and DIEU ET MON DROIT are part of the arms, FIFTY PENCE runs above and a large 50 sits below, and Ironside's initials CI are on this side. The heads side carries Ian Rank-Broadley's fourth portrait of Queen Elizabeth II with the date.