The Lords voted through Lord Ribeiro's bill - which was backed by many health campaigners and charities - on the nod last Monday. The Conservative peer said there was not strong government support for legislation in the area, with ministers favouring education as a way of persuading parents to change their behaviour.
He said most smokers did not do so while driving their children but there was a "hard core" of parents whose behaviour had to be addressed. The proposed legislation would "raise the ante" over the issue and remind ministers there were other options should their approach not succeed in protecting children from harm.
The measure would need the support of the House of Commons to become law.
