Your view: Vote to ban smoking in cars with children
MPs vote on Monday on plans to make it illegal to smoke in vehicles with children.
It is already against the law in several countries including the US, Canada and Australia.
Last month Lords unexpectedly backed Labour's call for a ban in England, leaving MPs to make a final decision.
The government doesn't think it is necessary and would prefer to concentrate on educating drivers about the dangers.
It's going to let coalition members make their own decision rather than follow party orders, making it harder to predict which way the vote will go.
Last week about 700 doctors and other health experts signed a letter urging politicians to back the ban.
Newsbeat spoke to people in Doncaster about the idea.
Twenty-year-old Becky Brown can remember her mum smoking in the car when she was younger.
"She always had the window down but it doesn't make much difference. You still inhale the smoke as it comes into the back of the car," she said.
"I do think a ban is a good idea. Of course you want the best for your children.
"But at the end of the day it's your car so you should be able to do what you want."
Despite that - Becky says she'd vote for a ban if she were an MP. Her partner Lee Robinson, 21, agreed.
"It is a good idea and something that's worth doing - the question is whether people are going to abide by it and what the punishments will be," he said.
Amber Musselwhite is 18 and doesn't have any children but has been smoking since she was 13.
"I'm alright and my dad smoked around me when I was little. At the end of the day you shouldn't smoke around your kids," she said.
She doesn't think a blanket ban is necessary and added: "It depends how old the kids are.
"If they're babies then no - but as long as you've got windows open and air conditioning on, it's like being a living room with a kid. You're obviously going to have a smoke."
Jack Shutt is 23 and a non-smoker but said there is no need to make it illegal.
"My mum and dad both smoked in the car when I was a kid. It never hurt me.
"At the end of the day it's each person to themselves. They've got ashtrays built into cars for a reason haven't they?"
These plans are for England only. Similar bans haven't been ruled out in Wales, Scotland or Northern Ireland, but there are no firm plans in place.
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