Texting while driving impairs motorists more than being under the influence of drink or drugs, research suggests.

The RAC Foundation found average reaction times slowed by 35% when 17 to 24-year-olds drove in a simulator while writing or reading texts.

Nearly 50% of drivers aged between 18 and 24 admitted to texting while driving, it said.

Previous studies had found reactions were 21% slower among those who had taken cannabis and 12% slower among those who had drunk to the legal limit. Texters drifted out of lanes more and had poorer steering control. Dr Nick Reed, senior human factors researcher at TRL, said: "When texting, drivers are distracted by taking their hand off the wheel to use their phone, by trying to read small text on the phone display and by thinking about how to write their message."

"This combination of factors resulted in the impairments to reaction time and vehicle control that place the driver at a greater risk than having consumed alcohol to the legal limit for driving."