In northern Scotland, the Neolithic never ended

“The natural assumption in a place like Brodgar is that it is built to last,” Edmunds continued. “If the stones are missing from the circle, it must be due to later intervention. In fact, chances are a lot of the stones had already fallen in the Neolithic. Some have solid foundations, but others are not so deep. If you were worried about long-term stability, you wouldn’t do it this way. Which tells us that a place like Brodgar is really a performance space. It’s the making of it that matters. New stones are added, others are removed. There’s a fluidity to it. That’s what we can never see, but we have to try Imagine it.

I followed Edmunds down to the River Ness, where the past ran back underground. A bulldozer operator was filling excavation trenches and restoring Brodgar Farm to its previous condition. No. 10, an imposing ceremonial building I previously toured with Nick Card, is no longer visible.

“The question of permanence comes up here as well,” Edmonds said. “After a few generations, Temple 10 suffered subsidence and had to be partially rebuilt. Over time, it became unusable. Finally, in around 2400 BC, it was closed in a massive ceremony that included the widespread slaughter of livestock.” These “switching off” festivals were common in the Neolithic: they involved knocking down roofs, trampling pottery, and breaking gneiss mace heads. Now, in a historic repeat that would have pleased George MacKay Brown, Structure 10 has been closed again.

The final stronghold was the elaborate Structure 27. After a congratulatory card and Tam at drilling headquarters, Edmonds headed there to take some final soil samples. “A building with a capital letter A,” he said, as if still amazed by the sight. There has been less decline here. The sheetrock that holds the building level varies by only a few centimetres.

“The orange-looking earth is ash from peat fires,” Edmonds said as he scraped the trench wall with a shovel. “There’s a layer of baked bone. It’s a large slab of pottery, which has disintegrated back into clay, leaving dark pieces of firestone that were used to create ceramics.”

Becky Little, an artist who leads classes in traditional methods of working with clay, was visiting Nice that day, and came to say hello. “We’re in our last days here,” Edmonds told her. “By the middle of next week, it will be all over.” Little climbed into a ditch and bent over a vertical stone carved with a grid of typically Orcadian geometric patterns. “I never saw that when I was here before,” Little said.

“The light is perfect for him now,” Edmonds replied. Orkney was having one of its brisk pastoral hours, the afternoon sun creating a world of pure green and blue.

I stopped for the last time at the stones of distress that have remained in my memory since I was seventeen years old. Despite the deluge of new data, megalithic rocks have given up none of their stubborn strangeness. They may not have been intended to last for thousands of years, but after they did, they are stone doors through which the living try to touch the dead. I had the feeling that my own life was a shadow flashing across the rock. Preoccupied with thoughts of time and death, and also anxious about missing the ferry, I got into my car and disappeared. ♦