Public Libraries 50p (2000)

A circulated Public Libraries 50p is worth face value: it was struck in large numbers for circulation and is still found in change. Premiums begin with brilliant uncirculated coins from the Royal Mint pack, then rise through the proof, silver proof and silver proof piedfort to the gold proof, the scarcest version. Those collector versions are priced for their finish and metal, and one kept in its original packaging is worth more than a loose coin.

With 11,263,000 struck for circulation, the Public Libraries 50p is the 72nd rarest of the 81 ranked 50p designs and has the 150th lowest mintage of all 194 circulating UK designs. That puts it in the Common band, for mintages 10,000,000 or more.

The next rarer 50p is the Diversity Built Britain 50p, with 10,300,000 struck, and the next more common is the Victoria Cross (medal) 50p, with 12,087,000 struck.

The book on top of a building with columns is distinctive, and the words PUBLIC LIBRARIES across the front of the building confirm it. Look for the pair of anniversary dates at the top of the tails side, the second one 2000, and the small discs inside the pediment. It is the modern small size, the same as the 50ps in change today, with Ian Rank-Broadley's portrait of the Queen on the heads side.

Known varieties of the Public Libraries 50p, all listed among the UK error coins and varieties:

• 2009 anniversary set reissue: Struck again dated 2009, with Ian Rank-Broadley's portrait, for the 16-coin set issued in October 2009 to mark 40 years of the 50p, in cupro-nickel and as silver proof, gold proof and gold piedfort. Not issued for circulation.

The Public Libraries Act, passed in the middle of the nineteenth century, first gave local boroughs the power to set up free public libraries. Its 150th anniversary fell in 2000, and the Royal Mint marked it with a 50p by Mary Milner Dickens, who had designed the 1992 EC Presidency 50p and would go on to design the 2003 Suffragettes coin. Her reverse mixes old and new. An open book, its pages caught as they turn, rests on the roof of a classical library building with columns and a pediment, and inside the pediment she placed compact discs. The words PUBLIC LIBRARIES run across the building near the bottom of the coin, set between two dots, and the two anniversary dates, the year of the Act and 2000, are spaced across the top. The value 50 PENCE sits to the right, above the building. On the heads side is Ian Rank-Broadley's portrait of Queen Elizabeth II.