Alex Cunningham, the MP behind the proposed bill to ban smoking in cars, has been given space on PoliticsHome in order to gain support. With regard to the question of toxins, Raedwald 'did the maths' in his post here (follow the link to the March post). Likewise, on the question secondhand smoke, Christopher Booker and Richard North debunked any claims in that area, here (follow link to post of 24th March 2010).
Cunningham writes that quite simply, this is a serious public health issue; that we have a duty to protect children from such harm, and the most effective way we can do that is through a ban on smoking in cars. In the interests of fairness and equality, perhaps Cunningham would also permit the electorate to point out that they, too, have a similar serious, public health issue. That is that we have a duty to protect ourself from the harm that politicians do - and the only way we can do that is to ban all politicians and their practices.