Video report by Wales and West of England Correspondent Rupert Evelyn
The origins of the huge “sarsen” stones of Stonehenge have been revealed after a core of one of the megaliths was discovered in the US.
Tests carried out on the core of stones, which were extracted during repair work in the 1950s, indicate the 20-tonne sarsens came from West Woods, near Malborough.
The core was originally removed by a Basingstoke diamond-cutting business as part of measures to use metal rods to reinforce one of the upright stones in 1958.
Employee Robert Phillips kept it in pride of place in his office, which he later took with him when he emigrated to the US, and its existence remained unknown for six decades.
Researchers only became aware of its existence when he expressed a wish for it to be returned on the eve of his 90th birthday.
His sons presented it to English Heritage, which cares for the World Heritage site, in 2018 and has helped answer the age-old question of where the stones came from.
Professor David Nash, from the University of Brighton, who led the research, said: “It has been really exciting to harness 21st-century science to understand the Neolithic past, and finally answer a question that archaeologists have been debating for centuries.”
He said it was the chance to analyse the returned core that enabled the experts to determine the source area for the enormous stones.
'One of those hair on the back of the neck moments': Professor Nash speaks to ITV News
“We’re incredibly grateful to the Phillips family for returning the core to us,” he added.
He said to ITV News: "Now we know that we’ve got a method that works, we can start addressing all sorts of other archaeological questions."
Research has shown the monument’s smaller blue stones come from specific spots in the Preseli Hills in Wales.
Archaeologist Katy Whitaker explains why she was surprised by the findings
But the question of where the ancient people who constructed Stonehenge quarried the sarsens from was unknown.
Marlborough Downs has long been presumed to be the site where the stones were taken from, but that has never been rigorously tested according to a study by a team of researchers published in the journal Science Advances.
The team used a non-destructive X-ray technique to assess the make-up of all the remaining sarsen upright and lintel stones, which established that 50 of the 52 remaining megaliths shared a consistent chemistry.
This led them to conclude they were sourced from a common area.
The core was cut up and sampled for its chemical composition, and compared with samples of sarsen boulders in 20 areas stretching from Devon to Norfolk, including six in the Marlborough Downs to the north of Stonehenge.
The analysis found that stone 58 – which the core was taken from – and therefore the majority of the sarsens were mostly likely from West Woods, which sits around 15 miles north of the stone circle.
The experts are planning further archaeological investigations to identify the exact location of the prehistoric quarry.
English Heritage senior properties historian Susan Greaney and one of the authors of the paper said it was a “real thrill” to track down the area that the builders of Stonehenge sourced their materials in 2500 BC.
“Now we can start to understand the route they might have travelled and add another piece to the puzzle.
“While we had our suspicions that Stonehenge’s sarsens came from the Marlborough Downs, we didn’t know for sure, and with areas of sarsens across Wiltshire, the stones could have come from anywhere.
“We can now say, when sourcing the sarsens, the over-riding objective was size – they wanted the biggest, most substantial stones they could find and it made sense to get them from as nearby as possible,” she said.