Is a ban on smoking in vehicles when children are present the nanny state gone mad, or an important public health measure? MPs debated the issue this week after the Lords sent back the Children and Families Bill with an amendment which empowered ministers to bring in a ban.
Although it only applies to England, Ian Paisley jnr was determined to point out its flaws. He told the House: "These important issues affect many jobs in my constituency."
Paisley said any person who lights up and smokes in front of a child "is a prat, in my view, and we as a House should not be legislating on that".
He added: "What we should really be engaging in is educating people. We do not require legislation to educate people not to be prats and to be sensible."
He also said the number of people smoking in cars with children present is "minuscule" and "a minor problem".
Mark Durkan questioned his logic. "If the number is so minuscule, why is the provision so disproportionate and excessive and how would it make enforcement impossible in the way he suggests?" he asked.
Paisley, Jeffrey Donaldson and around 100 Tory MPs, including Secretary of State Theresa Villiers, Welfare Secretary Iain Duncan Smith and Home Secretary Theresa May, voted against the amendment.
Some feared the "smug, patronising excesses of new Labour" would lead to a ban on people smoking in their home.
The issue was tricky for David Cameron. Labour whipped their MPs to vote for the amendment, while the prime minister gave his ill-disciplined troops a free vote, avoiding yet another rebellion.
His Right-wing backbenchers enjoyed the opportunity the debate provided to rant about Labour and the nanny state.
"The only reason they came into Parliament was to ban everybody else from doing all the things that they happen not to like," claimed Philip Davies.
The debate on the ban, which is now set to become law before the 2015 general election, neatly showcased the fundamental differences between the Tories and Labour.
Shadow Public Health Minister Luciana Berger said the ban was about "reducing the misery inflicted by passive smoking, saving millions of pounds for our NHS and protecting children who do not have a choice and do not have a voice".
Conservative MP Anne Main, on the other hand, called it "illiberal, nonsensical and unenforcable".
"We all want to protect children," she said. "In that case, perhaps, we should get out the fat callipers when we see very lardy children walking down our high streets, because their parents feed them junk of an evening.
"Perhaps we should ban fattening foods because there are more than a million people with type 2 diabetes, as has been said in the media today. Where will it stop?"
Lady Hermon, Mark Durkan and Margaret Ritchie voted for the ban, which was approved with a big majority.
No doubt a similar measure will be brought before the Assembly in due course and Northern Ireland will have its own debate on the matter of adult freedom versus child protection.