ONE of the most significant discoveries at Avebury World Heritage Site was announced this week after National Trust archaeologists discovered 17 huge Sarsen stones buried inside the massive stone circle itself.

The stones were thought to have been pushed over and buried in the 13th and 14th centuries, possibly at the behest of monks at the former monastery in the village.

It is known that some were dug up in the 17th and 18th centuries and broken up for building material.

Archaeologists are jubilant that so many of the stones, originally numbering 100, have survived.

But there are no plans to raise them, as it is feared this could damage the ancient stones.

Thirteen have been found in an arc under an area of turf in the south-east quadrant, to the Swindon side of the main circle.

It is the first time the National Trust has undertaken a geophysical survey of the area around the World Heritage Site.

Martin Papworth, the National Trust's archaeologist for Wessex, described the find as truly exciting. He said: "I am amazed no-one has thought of carrying out a geophysical survey before. Until now, no-one had realised that some of these stones had survived intact and that they actually lay buried next to their original location."

The Trust is considering using ground-probing radar to create three-dimensional images of each of the buried stones and raise them as computer images.