In a recent test, the most expensive cars proved the most dangerous as drivers tried to come to grips with the new technology.

The Mercedes Benz S Class came out worst. Testers putting drivers though several tasks found they spent almost one third of a 16mile test route with their eyes off the road while the car was in motion.

The BMW with its iDrive technology also fared badly. But a 1983 Mercedes Benz came out as the safest of 10 cars because the controls were not too sophisticated.

The tests were conducted by Auto Expressmagazine, which says many of us drive blind on a regular basis without being aware of it.

The Porsche 911 did surprisingly well for an expensive car - it came in just behind the Mercedes Benz 190, its drivers spending 113 seconds of the 16-mile trip with eyes off the road. The Porsche Driver scored 249 secs, Hyundai Santa Fe 279 secs, Opel Astra 297 secs, VW Golf 311 secs, Peugeot 207 340 secs, BMW 3 Series 351 secs, Audi A6 Allroad 398 secs, Ford Galaxy 425 secs, and the Mercedes Benz 468 secs.

Drivers undergoing the tests wore glasses which show how much time is spent looking at an object.