Openwork silver frame lined with gold and set transparent with diamonds; narrow band edged with pearls, surmounted by four crosses-pattée, the front cross set with a pale yellow brilliant, and four sprays representing the national emblems of the United Kingdom.

From its frequent appearance on postage stamps and coins, this exceptionally beautiful head ornament, incorporating the national emblems of England, Scotland and Ireland, is probably the most familiar piece of Her Majesty The Queen's jewellery. Set with 1,333 diamonds, including a four-carat pale yellow brilliant in the centre of the front cross, the diadem has been regularly worn (and slightly modified) by queens regnant and consort from Queen Adelaide onwards. This feminine association belies its origin, since it was made for George IV's use at his famously extravagant coronation in 1821. On that occasion, he wore it over a large velvet 'Spanish' hat at the ceremonies in Westminster Hall and during the walking procession to Westminster Abbey.

The order for the diadem was placed with Rundells in 1820 and work was complete by May of that year. The design, probably by Rundells' chief designer Philip Liebart, reflects something of the discarded plan for George IV's Imperial State Crown, which was drawn up by Liebart in the same period and was to have included the national emblems in place of the traditional fleurs-de-lis.

Together with a diamond-studded loop (which was broken up to help make Queen Victoria's Garter armlet) the bill for the diadem amounted to the large sum of £8,216. This included an £800 hire charge for the diamonds - stones were regularly hired for use at coronations up to 1837 - computed on a percentage of the value of the stones. When the coronation had to be postponed for a year on account of Queen Caroline's trial, a further hire charge was levied. Normally the stones would have been returned to Rundells after the coronation, but in this case there is no sign that the delicately worked diamond sprays and crosses, a masterpiece of the new transparent style of setting, have been disturbed. Equally, there is no evidence that the King purchased the stones outright, so it could be that the bill was met by a discreet barter of old stones from George IV's extensive collection.

Today the diadem is worn by Her Majesty The Queen when travelling to and from the State Opening of Parliament.

Catalogue entry from Royal Treasures, A Golden Jubilee Celebration, London 2002