One in four motorists in the UK use hand-held mobile phones while driving, research has found.
One in four motorists in the UK uses a mobile phone
One in ten people admitted sending text messages while driving, the Continental Research study found.
Out of 2,000 motorists surveyed, the majority who used a mobile phone while driving were males aged between 25 and 44.
Research spokesman James Myring said 9% of drivers still make calls and 10% write text messages while driving, despite the Department of Transport's law banning the use of hand-held mobile phones on 1 December.
A total of 15% read text messages, and 16% answered calls at the wheel.
"Many perhaps would not initiate a call or write a text whilst driving, but upon hearing the phone ring, cannot resist the temptation to answer a call or read the message," he said.
Around 35 million adults in the UK use a mobile phone.
Anyone breaking the law will receive an on-the-spot £30 fine - rising to a maximum £1,000 if their case goes to court.
Those caught breaking the ban would also get three penalty points on their driving licences for each offence.
Under current laws, motorists can only be prosecuted for using mobiles if they fail to keep proper control of their vehicle - there is no actual law specifically prohibiting the use of mobiles while driving.
Previous research has shown people using a phone while driving are four times more likely to have an accident, according to the government.
It is also warning users of hands-free phones they still risk prosecution for failing to have proper control of their vehicle or for careless or reckless driving.
Studies by the Transport Research Laboratory have suggested using a hand-held mobile is more dangerous than drink driving.
The practice is illegal in more than 30 countries.