Nearly 30pc of drivers send text messages while at the wheel, a new survey reveals.
And 8pc text-and-drive at least once a week, the poll by road safety charity Brake and insurance company Direct Line found.
The findings, based on responses from 841 drivers, follow a report which warned of increased levels of smartphone addiction by users who are unable to go long without checking their phone.
Brake and Direct Line said other research had shown that texting at the wheel can make drivers 23 times more likely to cause a crash and that using a phone to email or surf the web also causes serious distractions.
Studies in the USA have shown that incidents of death by distracted driving had increased, with researchers putting this down to increases in drivers using smartphones.
Brake campaigns director Julie Townsend said: "People who text, use the web or social networking when driving are taking enormous risks with their own and other people's lives.
"This kind of irresponsible behaviour is illegal and it kills so there should be no excuses.
"We are concerned that the increasing uptake of this technology could lead to more crashes and casualties caused by distracted drivers.
She said Governments should take action now to stop the upsurge in dangerous driving.
"It's vital that drivers listen to these warnings and make a pledge to never use their phone when driving," she said.