New research shows that drivers are still not getting the message when it comes to mobile phone use while driving - and social networking is a big problem.

According to the survey by road safety charity Brake and Direct Line, 21% of young drivers admit to using email, Twitter and Facebook while on the go - more than twice the proportion of 'older drivers'.

Alarmingly, 44% of young drivers say they text behind the wheel. Again, this is a far higher proportion than that of older drivers.

This is not the first time that the shocking extent of smartphone use behind the wheel has been revealed - so the message isn't getting through, despite the warnings.

Tests have shown that using a phone while driving can increase reactions to a greater extent than drink driving; a study by the transport Research Laboratory demonstrated that driver reaction times are 30% slower when using a hands free phone than when over the legal alcohol limit.

Brake's Julie Townsend said: "Use a phone while driving and you are taking a horrendous risk with your own life and the lives of others. We're urging people to drive smart, recognising that phone use at the wheel can and does destroy lives, and no call or text is ever that important.

"If you need to use your phone urgently, pull over somewhere safe first: it's as simple as that. We are also calling on the government to do more to tackle phone use at the wheel, including banning hands-free phones and bringing in far stiffer penalties."

Meanwhile, the Institute of Advanced Motorists (IAM) has claimed, in a press release called 'death wish of driving seat tweeters', that up to 80% of drivers are using smartphones behind the wheel.

Its research shows that using social networking sites on a phone slows reaction times by 37%, with 24% of 17-24-year-old drivers admitting they do it.

The IAM has published a handful of genuine posts from Twitter users, which it calls 'the worst dangerous driving tweets'.

The list includes one user who announced that 'if I'm ever in an accident while driving and tweeting and you're the first person to arrive on the scene, grab my phone and press "Send"', and another who said 'Multi-tasking: Driving, Tweeting & Brushing my hair. I do it. If I die remember me like John Lennon.'

The IAM's Simon Best said: "That someone should risk their life on the motorway to announce to the world that they are eating percy pigs [a reference to another tweet] is simply staggering.

"The government must take the lead and make sure that motorists understand the dangers of using smartphones. Phone manufacturers and social network operators can also help reinforce the safety message."