Huge stones thought to have been destroyed seven centuries ago have been found within Avebury stone circle. LEWIS COWEN meets the archaeologist whose 21st century equipment made the exciting discovery

THE history of Avebury stone circle over the past 700 years will have to be rewritten after the amazing discovery of 17 huge Sarsen stones buried within the circle.

National Trust archaeologists, using geophysical investigation equipment have found the stones within the existing circle, but buried one or two feet below ground.

It had been thought that the stones had been destroyed and used for building material in the 17th and 18th centuries.

Martin Papworth, the National Trust's archaeologist for Wessex, was brought in by the local custodians of the World Heritage Site two weeks ago to undertake the investigation using the "geofizz" machine, which maps out the underground contours of land using electrical impulses which are then mapped by computer.

He told the Gazette: "I can't understand why nobody thought of doing this years ago. On our first day we found stones that no one knew were there.

"This is a truly exciting find and completes the circle of Avebury. These stones were erected over 4,500 years ago and the world of archaeology suspected that most of these stones had been demolished and lost forever.

"We know that many of the Avebury stones still standing up to 300 years ago were broken up for building stone in the 17th and 18th centuries."

Many of the stones were pushed over and buried by local people during the 13th and 14th centuries. Mr Papworth said: "We don't realise now how religious these people were. They had suffered the Black Death and were looking around for a cause for their affliction. Stones erected by Pagans seemed as likely a cause as any, so they removed them from the sight of man."

In the 1930s, Dundee marmalade heir, Alexander Keiller, excavated and re-erected many of the stones that can be seen today, standing in the west half of the circle. However, the outbreak of the Second World War brought an end to his project.

Now, although the National Trust has no plans to raise the stones that have been so well protected by the earth for the last seven centuries, it is considering using ground-probing radar to create three-dimensional images of each of the buried stones and raise them as computer images.

Mr Papworth said: "The stones are safest where they are at the moment, but we have the technology to be able to show everyone their shape, size and how they would have looked when they were first erected."

The geophysical survey has been undertaken using a "geofizz" machine which measures the density of the earth at any particular point. A reading of more than 100 ohms identifies rock under the ground and with the use of pegs it is possible to mark the outline of the stone.

The measurements from the "geophizz" machine are automatically registered on computer and the area underneath the feet of the tourists is mapped. Mr Papworth and his team still have two or three days' more work on the site and he is confident that the 17 stones found so far, 13 of them in an arc in the south-east sector of the site, are not the end of their discoveries.

He said: "We are concentrating on an area where we think we might have found a circle of post holes, indicating that some other kind of structure lay there.

"That is the most exciting thing about investigating an area like this you never know what you may come across next."

Avebury is considered once of the most important megalithic monuments in Europe. It was built from 2800BC onwards and includes the largest stone circle in the world.