A tour guide that alerts motorists to key attractions has been launched for Garmin Satellite Navigation (Sat Nav) equipment.

RoadTour's software package featuring 600 historical UK sites, including castles and battlefields, provides a commentary for each place, as well as photos and visitors' information.

The idea has been in development for several years, said Daniel Taylor, managing director of RoadTour and inventor of the software.

"It's only during the last year that the devices have become powerful enough to make it happen," he said.

Research commissioned by RoadTour shows that 10 percent of 18-24 year olds think Stonehenge is in Norfolk.

A further 38 per cent of people believe that Hadrian's Wall is in Scotland and one in 10 think the Romans built the A1.

"A friendly reminder, which tempts us into exploring our heritage as we're driving up the M40 or wherever, seems to me to be altogether a good thing," said Taylor.