The new £1 coin and the United Kingdom’s largest coin

01 Feb 2017

Today (30 January), samples of some of the thousands of coins produced by The Royal Mint over the last year will be going on trial at the Trial of the Pyx, an ancient annual quality assurance ceremony. Among them will be the new £1 coin, and an imposing Kilo coin measuring 100mm wide, which was produced to celebrate the 90th birthday of Her Majesty the Queen. 

The existing £1 coin is to be superseded by a new bimetallic coin on 28 March 2017, so to ensure that there are sufficient numbers of the new 12-sided coin, The Royal Mint started striking them in Spring 2016. After the launch of the new coin in late March, the public are being urged to spend their ‘round pounds’ as soon as possible before 15 October 2017, as they will be re-used to make the new £1 coin.

At the Trial, samples of circulating and commemorative coins produced by The Royal Mint are selected at random and weighed for accuracy.  Now held at Goldsmiths’ Hall, London, the Trial was first recorded publicly in 1282, and is today presided over by the Queen’s Remembrancer or their deputy, who are amongst the highest legal representatives in the country, assisted by an independent jury of Liverymen of the Goldsmiths’ Company.  

During the ceremony jury members are presented with Pyx boxes (Pyx being the Roman word for chest). The coins are selected from a random selection provided by The Royal Mint and placed in copper bowls. The remainder are placed in wooden bowls and are then weighed for accuracy. The Trial is then adjourned until May to allow time for trial coins to be tested by Goldsmiths Assay Laboratory and the National Measurement Office.

Whilst modern methods such as XRF (X-Ray Fluorescence) are often used in assaying, it is still only the centuries old methods such as cupellation (the fire assaying of gold) that are accurate enough in the testing of metals and therefore remain credible for checking the accuracy of the coins of the realm for the Trial of the Pyx verdict.

Modern legislation does not mention penalties for an adverse verdict by the Pyx jury, yet there have been stiff punishments for failure in the past.   The Master of the Mint (today a role held by the Chancellor of the Exchequer) went to prison for six weeks in 1318 and even Sir Isaac Newton was at loggerheads with the jury during his time as master of the Mint when the integrity of his coin samples was questioned.

Whilst the Trial is steeped in ancient traditions, and attended by officers with some of the oldest job titles in the land (The Master and Deputy Master of the Royal Mint, The Queen’s Assay Master, The Queen’s Remembrancer), the Trial of the Pyx is as relevant today as it has always been, and continues to play an extremely important role, supporting The Royal Mint’s international reputation for excellence in production.