In a new twist, Open University geologists say the stones were in fact moved to Salisbury Plain by glaciers.

Last year archaeologists said the stones came from the Preseli Hills.

Recent research in the Oxford Journal of Archaeology suggests the stones were ripped from the ground and moved by glaciers during the Ice Age.

Geologists from the Open University first claimed in 1991 that the bluestones at one of Britain's best-known historic landmarks had not come from a quarry, but from different sources in the Preseli area.

The recent work was conducted by a team headed by Professor Olwen Williams-Thorpe, who said she and her colleagues had used geochemical analysis to trace the origins of axe heads found at Stonehenge and this backed up the original work.

There has been a great reluctance to allow facts to interfere with a good story Dr Brian John

"We concluded that the small number of axes that are actually bluestone derive from several different outcrops within Preseli," she said.

"Axes found at or near Stonehenge are very likely to be from the same outcrops as the monoliths, and could even be made of left-over bits of the monoliths."

The research

Archaeologists claimed the stones came from a quarry at Carn Menyn

Dr Brian John, a geomorphologist living in Pembrokeshire, said he always thought the idea that Bronze Age man had quarried the stones and then taken them so far "stretched credibility".

But he said the debate would go on until someone was able to prove beyond doubt what happened one way or the other.

"This is very exciting, and it moves the bluestone debate on from the fanciful and unscientific assertions of the past," he said.

"Much of the archaeology in recent years has been based upon the assumption that Bronze Age man had a reason for transporting bluestones all the way from west Wales to Stonehenge and the technical capacity to do it.

"That has been the ruling hypothesis, and there has been a great reluctance to allow facts to interfere with a good story.

"Glaciers may move very slowly, but they have an excellent record when it comes to the transport of large stones from one part of the country to another."