The British Medical Association, which has described its proposed ban as ‘bold and courageous’ ban, says the move is related to reasons of health rather than road safety.

Toxin levels from smoking in a closed vehicle can be 23 times higher than in a typical smoky bar, it is claimed, putting children and the elderly at particular risk.

Dr Vivienne Nathanson, of the BMA, said there are more than 80,000 annual deaths in England  caused by smoking.

“The UK made a huge step forward in the fight against tobacco by banning smoking in all enclosed public places but more can still be done,” Nathanson said.

“The current UK Government prefers voluntary measures or ‘nudging’ to bring about public health change, but this stance has been shown to fail time and time again.”

However, a Department of Health spokeswoman said: ‘We do not believe that legislation is the most effective way to encourage people to change their behaviour.”

Th spokesperson did say that a national marketing campaign would be launched next year to remind smokers of the risks of exposing children and adults to second-hand smoke.

The BMA’s message coincides with the second reading of a Private Members’ Bill, on November 25, calling for a smoking ban in vehicles when children are present.

Simon Clark, of smokers’ group Forest said: “There is no justification for a ban in cars, with or without children present.

“Legislation is a gross over-reaction. What next, a ban on smoking in the home?”

And PM David Cameron, a former smoker, recently signalled his opposition to a car ban. He praised the success of the public places smoking ban, which he opposed at the time, but added: “I am much more nervous about going into what people do inside a vehicle.”