Plans to ban smoking in cars when children are present have won support in the House of Lords, but the measure would need support of MPs to become law.
The private member's bill proposed by Lord Ribeiro to make offenders liable for a £60 fine or attendance at a smoke awareness course was approved by peers, reported BBC News.
The measure would need government support and David Cameron has questioned whether it is a justified move, suggesting it has severe implications for personal freedoms.
According to the BBC, Cameron told MPs last year that while he backed the ban on smoking in pubs, he felt "more nervous" about prescribing what people should and should not do in private vehicles.
But Lord's voted through the bill yesterday, which, unsurprisingly, is backed by many health campaigners and charities.
Tory peer Lord Ribeiro 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 it was a small minority of parents who smoked while driving their children but the proposed legislation would "raise the ante" over the issue.