Nearly half of UK motorists use a mobile phone while driving, and two-thirds of those do so without using a hands-free adapter, a survey for the road safety organisation, Brake and car insurance provider, Direct Line has found.

A quarter of respondents talk on their phone at the wheel at least once a week.

Brake and Direct Line are launching a campaign urging drivers to 'drive smart' by putting their phones out of sight and out of mind while driving. They are warning that using a hands-free or hand-held phone at the wheel can lengthen reaction times to a similar extent to drink driving.

Men are slightly more likely to chat on a phone than women (50% compared to 47%) and young drivers are slightly more likely than older drivers (52% compared to 48%). However, far more young drivers than older drivers break the law by not using a hands-free adapter (41% compared to 30%).

Young drivers are also far more likely than older drivers to use their phones to text, email or surf the web at the wheel.

Research into the impact of sending or receiving text messages among young drivers found the amount of time drivers spent with their eyes off the road increased by up to 400%. Drivers made 28% more lane excursions and 140% more incorrect lane changes.

Andy Goldby, Director of Motor Underwriting and Pricing, said: "Driving whilst using a hand-held phone is against the law, yet many drivers continue to flout it. Whilst it is legal to speak 'hands-free' it's just as distracting, and even the slightest distraction whilst driving can have the gravest consequences."