Motoring and safety groups in the Uk yesterday reacted with shock and anger at a survey showing a "significant" increase in illegal use of hand-held mobiles by drivers.
The poll from the Transport Research Laboratory showed driving with hand-held mobiles had risen sharply between 2008 and 2009 for car, taxi and van drivers.
The figures, involving more than 14,000 London drivers, were also higher than for 2006, the last year before tougher penalties for using mobiles at the wheel were introduced in February 2007.
"I am shocked by these figures and the concern is that, generally, the level of enforcement of the law is low," said AA president Edmund King.
Sarah Fatica, from road safety charity Brake, said: "It is incredibly worrying that people still don't take seriously the dangers that talking on your phone while driving pose."
Similar surveys by TRL in 2007 and 2008 had shown a fall in the number of drivers using hand-held mobiles following the February 2007 law changes.
But the most recent survey of 11,851 cars and taxis and 2,410 vans at 33 sites in London showed more road users are flouting the laws.
In the 2006 survey. 2.6 per cent of car drivers used hand-held mobiles while at the wheel. This figure dropped to 1.4 per cent in 2007 and was at 1.9 per cent in 2008, before soaring to 2.8 per cent this year.
The number of taxi drivers using hand-held mobiles was 1.1 per cent in 2006 and went down to 0.6 per cent in 2008 before rising to 1.6 per cent this year.
Van driver hand-held figures were 3.8 per cent in 2006, 1.8 per cent in 2007 and 2.7 per cent in 2008 before rising to 4.5 per cent this year.
The TRL report said: "In 2009, a significant increase in the use of hand-held mobile phones was observed for the drivers of all vehicles (in the London survey)."
The highest number of offenders were to be found in north east London.
The survey showed that men were more likely to flout the mobile phone rules, with the exception of the 17-29 age group.
Men aged 30-59 were most likely to use hand-held mobiles while at the wheel, while women aged 60 or more were least likely to do so.
TRL said the overall use of hand-held mobile phones by all drivers was seven per cent in the London 2009 survey.
Mr King said: "There has been a reduction in the number of traffic police and the proportion of people prosecuted for using hand-held mobiles is low.
"The worry concerning these survey figures is that you are four times more likely to have an accident if you are talking on a hand-held mobile while at the wheel."
Ms Fatica said: "It is clear that people are persistently using hand-held mobiles despite all the warnings. People have to ask themselves if making a phone call is really worth risking their life for.
"We would certainly support more enforcement of the mobile law. Quite clearly, people think they won't get caught. Perhaps the fines should rise from the current level of £60 to something like £500 to £1,000."
RAC spokesman John Franklin said: "These figures are a real cause for concern. Driving while using a hand-held mobile phone is dangerous and dramatically increases the risk of causing a serious accident - it's as simple as that. The issue of texting and its inherent dangers should also be remembered when addressing these figures.
"Clearly, all parties need to do more to tackle this issue because it's not going to go away of its own accord. Stronger law enforcement is undoubtedly needed, but greater education must play a central role as well."