SMOKING in cars should be banned to protect people - particularly children - from harmful tobacco fumes, doctors have said.
The British Medical Association (BMA) conference yesterday backed calls to ask UK governments to introduce legislation to ban smoking while driving.
Doctors were told the concentration of harmful chemicals in a car was 27 times higher than in a smoker's home and 20 times higher than in a pub before smoking bans were introduced.
Health campaigners yesterday welcomed the backing from the BMA, while smokers' lobby group Forest said there was no justification for a ban.
Addressing the conference in Cardiff, Dr Douglas Noble, from the BMA's public health committee, said second-hand smoke continued to have a huge effect on people's lives.
"The data on toxicity is extensive," he said.
"But let me give you one headline to remember - it would be safer to have your exhaust pipe on the inside of your car than smoke a cigarette, in terms of fine particulate matter released.
"And evidence suggests rolling down the window doesn't eliminate the problem."
Dr Noble said a change in law was needed to protect non-smokers, particularly pregnant women and children, travelling in cars.
He said research had found that more than half of eight to 15-year-olds had been exposed to smoking in cars and 86 per cent of children wanted people to stop smoking in vehicles.
"Heartbreakingly, almost 25 per cent of children were too afraid to ask the adult to stop smoking," Dr Noble added.
He said surveys of the public also backed a ban on smoking in cars.
But not all delegates at the conference backed the calls for a car smoking ban.
Callum Wood, from the medical students committee, said he felt a ban on smoking in cars was an unreasonable intrusion into people's private lives.
He also said it could be difficult to enforce a law, as well as driving people who used to smoke in their cars into smoking more in the home. "I don't think it is going to make a huge impact on health," Mr Wood said.
Mark Sanford-Wood, from the BMA GPs' committee, added: "You already have a legal duty to control your vehicle.
"This proposal adds nothing to that but seeks to criminalise ordinary and decent, law-abiding folk who simply choose to smoke."
But Dr Hamish Meldrum, the BMA chairman, pointed to the success of a ban on smoking in cars with children in them which had been introduced in Western Australia.
And Professor Averil Mansfield, chair of the BMA's board of science, also backed the motion, pointing to the impact on children in a car with smokers.
The majority of BMA members agreed, backing the call for legislation during a vote on the issue.
Dr Charles Saunders, joint deputy chairman of the BMA's Scottish Council, said: "Tobacco smoke is a potent cocktail of over 4,000 toxins, including 50 known to cause cancer. Smoking in the confined space of a car is a toxic threat to health.
"Children exposed to smoking in cars will be at risk of the harmful effects of second-hand smoke including persistent wheeze and respiratory disorders."
Dr Saunders added: "The SNP government, in its election manifesto, made a commitment to develop a new ten-year tobacco strategy for Scotland. I urge them to consider this as an important part of the next steps towards creating a smoke-free Scotland."
Other health bodies have already backed a ban on smoking in cars, including the Royal College of Physicians and the British Lung Foundation.
A Scottish Government spokeswoman said: "While we have no plans to extend the smoke-free laws to private cars, the Scottish Government is conscious that cars are now one of the main places for exposure of children to second-hand smoke."