Should people be allowed to smoke in cars?

Scientists say that smoking in cars creates dangerous levels of pollution - and it should be banned. It means that any child sitting in the back of a car while someone smokes breaths in high levels of smoke - which is really bad for them. At moment, smoking in cars is not against the law in the UK. But what do you think? Should smoking in cars be banned? Is it fair that passengers have to breath in other people's smoke?