There were worried frowns among the freemasons of Lodge Kirkwall Kilwinning last Thursday evening as images of a familiar old sailcloth crossed their television screens. “That’s put us in the spotlight for the loony brigade again,” muttered one disgruntled member.

What concerned them was the use by Channel 4 of images of the Kirkwall scroll in a documentary on the “Grail Trail” mania inspired by Dan Brown’s thriller The Da Vinci Code.The 18ft-long roll of material has hung undisturbed in the lodge for more than 200 years, fiercely protected by the brothers.

It first achieved a wide public notoriety five years ago when it was identified as a medieval treasure, said to be worth £4m, second only in value to the Mappa Mundi in Hereford Cathedral.

The Orkney textile was alleged to hold the key to ancient knowledge taken by Knights Templar from the Holy Land during the Crusades and passed on into freemasonry for safekeeping by the St Clair family of Roslin.

The same family was also responsible for building Rosslyn chapel near Edinburgh, an important stop on the trail for those tourists inspired by Brown’s novel.

These large claims about the scroll were inspired by Dr Andrew Sinclair of Churchill College, Cambridge, who had examined the textile, obtaining threads for carbon dating. His 2001 book, The Secret Scroll, purported to show that the Kirkwall scroll had been taken from the scriptorium of Rosslyn Castle to Orkney.

The masons of Orkney begged to differ, and now have found an ally in Bob Cooper, the curator of the museum and library of the Grand Lodge of Scotland in Edinburgh.

According to Cooper: “It is a well-known fact that radiocarbon dating is essentially for calculating the age of things in thousands of years, not hundreds. The results translate into a very wide range.” The scroll is, he believes, an 18th-century cloth, as the local lodge has always believed. Documentation shows it was gifted in 1796.

For his part, Dr Sinclair concedes that the side panels of the scroll do indeed include 18th-century imagery. But overpainting, he says, merely hides evidence of Templar symbols.

And he bats away suggestions that carbon dating is unreliable — after all it is used worldwide to place artefacts in a historical time frame.

“I believe (it) was originally a Templar strip map of the 5th and 7th crusades,” argues Sinclair. “I agree it was probably used as an 18th-century floor cloth, but the depiction of the hermaphrodite Adam and Eve in the middle section, showing a Gnostic scene of paradise, is much older, and has not been overpainted.”

That is of great significance, he says. “Underneath it are dozens of masonic and Templar emblems, and the whole artefact is unique in terms of Templar history.”

While Cooper agrees the scroll’s middle section is one of masonic significance, he argues that the masonic symbols on the central panel weren’t used before the 18th century.

“That’s the trouble when academics who are not freemasons try to make historical claims without knowing what lies behind the symbols,” he said.

“Freemasonry, as we know it today, didn’t exist in medieval times. Scottish stonemasons carved symbols but they weren’t these symbols — and they’re certainly not Templar in origin.”

The tale looks set to spin a while yet. A recent visit to the lodge by a textile expert doing research on floorcloths has only fanned the flames of controversy. Sarah Randel, from Sydney University, backed the lodge’s view.

“This woman had no axe to grind; she just took one look at it and said: ‘Floorcloth: iconography doesn’t predate the 18th century and material lines could indicate folds in a single piece of cloth’,” said David Partner, a local historian and past master of the lodge.

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