The Trial of the Pyx is a judicial ceremony dating back to the twelfth century.

Trial of the Pyx London Illustrated NewsAt the Trial of the Pyx on 6 December 1854, members of the jury take the oath in the presence of the Lord Chancellor, as shown in the London Illustrated Gazette.

From 1870, the Trial of the Pyx has taken place each year at the Hall of the Worshipful Company of Goldsmiths, London.

The name Pyx refers to the chests in which the coins are transported, and derives from the Pyx chamber in Westminster Abbey where historically the chests were kept. Little has changed in the procedure since the reign of Henry III; throughout the year, coins are randomly selected from every batch of each denomination struck, sealed in bags containing 50 coins each, and locked away in the Pyx boxes for testing at the Trial.

The Jury will usually consist of leaders in the financial world and at least six assayers from the Worshipful Company of Goldsmiths which have two months to test that the coins are within the statutory limits for metallic composition, weight and size. The benchmark against which the coins are tested is called a Trial Plate. Trial plates are held by the UK National Measurement Office.

The Trial will then reconvene and the Queen’s Remembrancer will ask the Jury for its verdict.

Trial of the Pyx jury

The delivery of the verdict is given in May in the presence of the Master of the Royal Mint, the Chancellor of the Exchequer, or his Deputy.

Trial of the Pyx Fact File

  • The Trial is held annually at London’s Goldsmiths Hall in accordance with the Coinage Act of 1870, and is presided over by the Queen’s Remembrancer of the Royal Courts of Justice, the oldest judicial office in the UK, dating back to the twelfth century.
  • The oldest surviving Trial Plate, now preserved in the Royal Mint museum, is of silver, dating from 1279.
  • Trial Plates today are made from pure metals of platinum, gold, silver, copper, nickel and zinc.
  • The Trial Plates used to be kept in the safe custody of the Exchequer at Westminster, but are now entrusted to the UK National Measurement Office along with the original coin Standard Weights against which the weight of the trial coins are compared.
  • Besides the annual Trial of the Pyx, rigorous quality tests are continually carried out during coin production to ensure that all coins produced at the Royal Mint conform to their correct specifications.
  • In November 1991, the Royal Mint became the first Mint in the world to be accredited to the international quality systems standard ISO 9001.