A Royal Family trip down the rabbit hole with King Charles, Queen Camilla, Prince William and the Order of the Thistle

From the Unicorn Pursuivant to a chap called Green Rod, a curious cast of characters gathered at St Giles’ Cathedral for a ceremony both laced with the ancient and touched by the fantastical.

The Most Ancient and Most Noble Order of the Thistle assembled on Wednesday to install its new Knights and Ladies, all handpicked by King Charles III to receive the often-called highest honour of the land. As well as selecting his wife and brother Edward for the accolade, his choices aim to reflect Scots of the greatest calibre, of the greatest public service and those who have changed the game in their respective fields.

New members include a forensic anthropologist, a lawyer and women’s rights campaigner and Scotland’s first black professor, who has done much to illuminate the nation’s deep links to slavery.

King Charles III and Queen Camilla leave after attending the Order of the Thistle Service at St Giles' Cathedral in Edinburgh. Picture: Andrew Milligan/PA Wire

It is a ceremony high on costume, fanfare and pageantry. If Lewis Carroll had cast his looking glass cast over the High Kirk, he may well have found inspiration. Central to ceremonies like these are the officers of the Court of the Lord Lyon, the heraldic authority of Scotland who, dressed in deeply woven tabards of red, gold and blue, appear as if they have sprung out of a deck of playing cards looking for their Queen of Hearts.

Meanwhile, the Royal Company of Archers, the King’s Bodyguards in Scotland, show the congregation to their seats in a show of Balmoral Bonnets decorated with the largest of eagle feathers. Long bows are at the ready.

As the rabbit hole of the royal occasion deepens and temporal matters begin to fade, the organ builds, trumpets flare and the choir cranks up through the gears until the vocals gather like the lightest of clouds beneath the 900-year-old vaults. Friends and family of the order gather, guests crane their necks and a child fidgets then falls asleep in her blankie, oblivious to the elaborate proceedings building around them.

King Charles III and Queen Camilla (centre left) with the Duke of Edinburgh (right) leave after attending the Order of the Thistle Service at St Giles' Cathedral in Edinburgh, for the installation to the Order of the Queen, the Duke of Edinburgh, Baroness Black of Strome LT, Baroness Kennedy of The Shaws LT and Sir Geoff Palmer KT. Picture: Andrew Milligan/PA Wire

As the King and Queen edge closer up the Royal Mile, where a modest crowd has gathered to show support and catch a look, members of the Order of the Thistle start to appear at the kirk’s West Door to welcome them, their ample hats of black velvet decorated with trembling white ostrich feathers.

Together, the Knights and Ladies represent hundreds of years of experience, duty and achievement. Baron Mackay of Clashfern, former Lord Advocate and retired Conservative Peer, is now 96, for example. Former Liberal MP, leader and peer The Lord Steel of Aikwood is now 86. Lord Cullen, former Lord President of the Court of Session, is a couple of years older.

As a minor delay to the royal arrival lengthened, the heavy chains of pageantry pulled and the deep folds of green mantle weighed a little, with some of the order needing a quick seat to sustain them. The order has the motto Nemo Me Impune Lacessit – or No One Provokes Me With Impunity – which it shares with the Royal Regiment of Scotland. Although there in St Giles’, the order appeared a little delicate in parts.

Order of the Thistle members leave after attending the Order of the Thistle Service at St Giles' Cathedral in Edinburgh, for the installation to the Order of the Queen, the Duke of Edinburgh, Baroness Black of Strome LT, Baroness Kennedy of The Shaws LT and Sir Geoff Palmer KT. PIC: Andrew Milligan/PA Wire

Then, in came the Duke of Rothesay – Prince William, if you will – all broad shoulders and able stare. Next to him is his uncle, the Duke of Edinburgh, who most will know as Prince Edward.

Both he and Queen Camilla were appointed as “extra” members of the Order on the accession of King Charles III, as is the norm of these things. All are dressed in the same flowing green velvet cloaks and ostrich feathers. On their bodies is the insignia of the order, a star made up of a St Andrew's cross with a green thistle on a field of gold. White ribbons flow, gold chains glisten.

Then, the order moves through the High Kirk – and disappears.

More craning of necks follows as eyes try to find the royal party, but proceedings switch to audio only for the congregation as the installation continues out of sight behind the doors of the tiny Thistle Chapel.

It was built just over 100 years ago to give a home to the present-day order, which was largely created in 1687 by James VII of Scotland. Then, he ordered the nave of Holyrood Abbey to be adapted for the order, which rewarded those who shared his political and religious aims. The following year, the abbey was ransacked by an Edinburgh mob furious at the King’s Catholicism. After that, the Knights of the Thistle had no chapel of their own for over 200 years.

Designed by Robert Lorimer and finished in 1911, the Thistle Chapel contains stalls for the 16 knights, the Sovereign’s stall and two royal stalls. The chapel is beautifully detailed in both religious and heraldic symbolism. Angels playing bagpipes can be seen above.

As the order vanished, the proceedings were delivered through speakers into the body of the kirk. A quick volume adjustment and the ceremony transmits in the careful tone of the King, who leads the installation with the help of Green Rod, whose real name is Rear Admiral Christopher Layman, a veteran of the Falklands War.

First to be installed is Queen Camilla, who is taken to her stall in the chapel to the right of the King by the Duke of Buccleuch, chancellor to the Order.

Behind her is The Duke of Edinburgh, then forensic anthropologist The Lady Black of Strome, lawyer The Lady Kennedy of the Shaws and human rights activist and scientist Sir Geoff Palmer. All face the King in the tiny chapel where only the royals have cushions.

The service becomes a mouthful of title and Christian observance, with the new Knight and Ladies swearing to fortify and defend the Christian religion to the utmost of their power. Promises to maintain the honour and dignity of the Order of the Thistle Follow, as does a commitment never to bear treason to the King. These words would have been similar to those spoken by the order in the 17th century to a monarch whose number was almost up. At St Giles’, the private, intimate chapel must have been an electric sight in those moments. But through the speaker, the words sounded, if not noble and ancient, then almost certainly a little fragile.