ANNOYED by all the drivers you see wandering out of lane while texting? It could be the tip of the iceberg – many more are simply daydreaming, according to a poll by the Institute of Advanced Motorists.

Forty per cent of drivers admit to not concentrating behind the wheel, with 24% citing daydreaming as the most common reason.

Young drivers are the worst offenders, with 50% of 18-24-year olds admitting they do not concentrate 100% of the time, and 30% citing daydreaming as the most common cause.

The IAM poll of nearly 1,500 drivers found 73% of over-65s said they concentrated at all times while driving.

But 47% of 24-34-year-olds admitted not concentrating all the time.

Twenty-two per cent of drivers cited stress as a reason for not concentrating, and 21% said they were thinking about what they would be doing on arrival. Another 21% said their minds were on family, friends and personal relationships.

There were also regional differences, with Londoners most likely to be not concentrating.

Just as well there's hardly any traffic there.

IAM chief executive Simon Best said: "Signs of not concentrating such as missed turnings or uncancelled indicator lights are commonplace. Simply not concentrating is a key cause of crashes yet it is not borne out in statistics because drivers rarely admit to it in police reports or on insurance forms.

"These results reconfirm stereotypes surrounding younger drivers and the ease with which they can be distracted away from staying safe. The key is to build up as wide a range of experiences as possible as you learn and to look upon your driving as a skill that needs continuous improvement."

Here's how the country was split:

Region % who admit not concentrating

London 47

Yorkshire and Humberside 46

South West 46

Scotland 46

East 42

East Midlands 40

North West 39