A coronation supertunica in the form of a full-length, sleeved coat of gold silk, opening at the front, with a narrow strip and wider band of foliate-embroidered ornament to either side and lined with red tabby silk; with a belt similarly embroidered and with a gold buckle cast with roses, thistles and shamrocks.

The Supertunica is the garment worn under the Imperial Mantle. The Supertunica, like the other coronation robes, relates to priestly vestments, and although this particular garment dates from the twentieth century its form has changed little since medieval coronations. This link with priestly robes was a reminder of the divine nature of kingship. The sovereign is invested with the Supertunica following the anointing ceremony.