They spent countless hours on weather-battered Scottish hills, a hardy band of geologists searching for the origin of one of Stonehenge’s most intriguing features.

But the prehistoric monument tends to yield its secrets reluctantly, and a new scientific report reveals that the origin of Stonehenge’s altar stone remains elusive – and the wind-whipped geologists may very well have been looking in the wrong spot anyway.

One described the altar stone’s beginnings as an “enigma”, another a geological detective story with no neat ending so far.

It all felt different in 2024 when specialists from universities in London, Wales and Australia examined grains of sandstone from the altar and hypothesised it came from north-east Scotland , more than 400 miles from Stonehenge.

A member of the team described the find as “jaw-dropping” and it led to speculation about how the six-tonne stone had been transported – by sledge or ship?…