Ancient man used stone hills to navigate like GPS.

Prehistoric man navigated his way across England using a crude version of 'sat nav' based on stone circle markers, historians have claimed.

They were able to travel between settlements with pinpoint accuracy thanks to a complex network of hilltop monuments.

These covered much of southern England and Wales and included now famous landmarks such as Stonehenge and The Mount. New research suggests that they were built on a connecting grid of isosceles triangles that 'point' to the next site.

Many are 100 miles or more away, but GPS co-ordinates show all are accurate to within 100 metres.

This provided a simple way for ancient Britons to navigate successfully from A to B without the need for maps.

According to historian and writer Tom Brooks, the findings show that Britain's Stone Age ancestors were "sophisticated engineers" and far from a barbaric race.

Mr Brooks, from Honiton, Devon, studied all known prehistoric sites as part of his research.

He said: 'To create these triangles with such accuracy would have required a complex understanding of geometry.

'The sides of some of the triangles are over 100 miles across on each side and yet the distances are accurate to within 100 metres. You cannot do that by chance.

'So advanced, sophisticated and accurate is the geometrical surveying now discovered, that we must review fundamentally the perception of our Stone Age forebears as primitive, or conclude that they received some form of external guidance.

'Is sat-nav as recent as we believe; did they discover it first?' Mr Brooks analysed 1,500 sites stretching from Norfolk to north Wales. These included standing stones, hilltop forts, stone circles and hill camps. Each was built within eyeshot of the next.

Using GPS co-ordinates, he plotted a course between the monuments and noted their positions to each other.

He found that they all lie on a vast geometric grid made up of isosceles 'triangles'. Each triangle has two sides of the same length and 'point' to the next settlement.

Thus, anyone standing on the site of Stonehenge in Wiltshire could have navigated their way to Lanyon Quoit in Cornwall without a map.

Mr Brooks believes many of the Stone Age sites were created 5,000 years ago by an expanding population recovering from the trauma of the Ice Age.

Lower ground and valleys would have been reduced to bog and marshes, and people would have naturally sought higher ground to settle.

He said: 'After the Ice Age, the territory would have been pretty daunting for everyone. There was an expanding population and people were beginning to explore.

'They would have sought sanctuary on high ground and these positions would also have given clear vantage points across the land with clear visibility untarnished by pollution.

'The triangle navigation system may have been used for trading routes among the expanding population and also been used by workers to create social paths back to their families while they were working on these new sites.'

Mr Brooks now hopes his findings will inspire further research into the navigation methods of ancient Britons.

He said: 'Created more than 2,000 years before the Greeks were supposed to have discovered such geometry, it remains one of the world's biggest civil engineering projects.

'It was a breathtaking and complex undertaking by a people of profound industry and vision. We must revise our thinking of what's gone before.' Was this simply for navigation, or some sort of ritual enlightenment?