Eight out of ten drivers (84%) have driven even though they were 'very tired', according to an AA-Populus Driver Poll.

The study of more than 17,500 drivers found that a 'long, hard day at work' is the most common reason for people driving while tired with two fifths (39%) doing so.

The study also found that Scottish drivers are the sleepiest (86%) and women are more likely than men to have driven tired while suffering from a lack of sleep the night before (29% compared to 25%).

Nearly half (43%) of 18 to 34 year olds feel tired because they are driving late at night and almost a third (31%) of men have drivev tired because they tave tried to cover too much distance in one day.

While driver fatigue is difficult to prove as the sole cause of an accident, some studies suggest that up to 20% of all accidents can be attributed to sleep.

In 2015 there were more than 2,500 casualties where driver fatigue was indicated as the main contributory factor in a road traffic incident.

Commenting on the findings Edmund King, AA president, said: “The dangers of speeding drivers are well known, but tired drivers can also pose serious risks to themselves and others.

“Drivers need to be alert at all times, and some will take meagre steps to try and stay awake such as winding down the window or turning up the radio.

“While this may have a short-term impact, a tired driver poses risks to others as their reaction times and observation skills are significantly diminished.

“If you find yourself feeling sleepy behind the wheel you should stop and rest in a safe place until you feel comfortable to drive again.

“Stopping for a coffee or a short nap could make all the difference between getting home to be safely tucked-up in bed or using your airbag as a pillow.”