All phone calls behind the wheel should be banned by law, say MPs, as using hands-free is as dangerous as making a hand-held call.
The Commons transport committee said the Government should consider making hands-free calls a criminal offence with fines of at least £200 and six penalty points on a licence.
The MPs said research showed the “cognitive distraction” from hands-free calling made it four times more likely a driver would crash, the same as with a hand-held call.
Dr Shaun Helman, a chief scientist at the Transport Research Laboratory, which advises Governments, said the risks were as great - if not worse - than having drunk enough alcohol to be at the legal limit for driving.
Research also showed that for about five minutes after ending any call in a car, drivers were still at “significantly increased risk of being involved in a collision.”
The MPs said the number of people killed or seriously injured in phone-related accidents has risen steadily since 2011 while police enforcement has plunged by more than two-thirds from 160,000 penalty notices in 2011 to 50,000 last year.
In 2017, there were 773 casualties on Britain's roads - including 43 deaths and 135 serious injuries - from crashes where a driver using a mobile was a contributory factor.
The MPs warned that the Government’s failure to outlaw hands-free calls was creating a “misleading impression” that it was safe. Given the risks were as great as with a hand-held, “it is inappropriate for the law to condone it by omission,” they added.
The RAC claimed a ban would hamper companies that needed to contact delivery drivers or taxis and pointed to difficulties of catching drivers doing it.
But the MPs agreed with evidence from psychologist Dr Gemma Briggs, a senior Open University psychologist, who said: “Just because something is difficult does not mean that we should not do it.”
They cited trials of new cameras and technology by at least two police forces - Hampshire and Thames Valley - where roadside sensors can detect a signal if a phone is being used in a car.
Surveys suggested illegal use of phones rose last year with a quarter of drivers admitting making calls while driving despite an increase in penalties in 2017 - from £60 to £200 and three to six penalty points. “There is already evidence that bad habits are creeping back in,” said the MPs.
They urged the Government to consider increasing the penalties further as a deterrent and called for a “step change” in educating the public with campaigns to persuade people that “using a mobile phone while driving is as socially unacceptable as drink driving”.
Potential loopholes in the 2003 ban should also be closed with an explicit new law banning all hand-held mobile phone use “whether for communicative purposes or not.”
The MPs also welcomed the transport department’s review of transport policing after the number of road traffic officers has fallen by a third in ten years from 3,766 to 2,643.
"Offenders also need to know there is a credible risk of being caught, and that there are serious consequences for being caught,” said Lilian Greenwood, the committee’s chair.
The transport department admitted it had not carried out an assessment of hands-free mobile phone use in cars.
Baroness Vere, transport minister, said: “If someone drives poorly because they are distracted by a phone conversation, for example, even if using hands-free, then the police can take enforcement action for failing to have proper control of the vehicle.”
The Committee however demanded the Government come forward with proposals to tackle use of phones including a ban on hands-free by the end of this year.
Ms Greenwood said: "Despite the real risk of catastrophic consequences for themselves, their passengers and other road users, far too many drivers continue to break the law by using hand-held mobile phones.
"If mobile phone use while driving is to become as socially unacceptable as drink-driving, much more effort needs to go into educating drivers about the risks and consequences of using a phone behind the wheel.
"There is also a misleading impression that hands-free use is safe. The reality is that any use of a phone distracts from a driver's ability to pay full attention and the Government should consider extending the ban to reflect this."