BBC News, Liverpool
An anti-smoking group in Liverpool is calling for all movies with smoking scenes to be given an 18 certificate.
The main character in Good Night and Good Luck chain-smoked
SmokeFree Liverpool told BBC's Radio 5 Live it wanted to see the change but the film classification board said the idea was "heavy-handed".
The push - backed by the city council - comes amid research showing young people pick up the bad habit from watching films containing smoking.
One city official said Liverpool may even act alone to restrict film access.
Andy Hull, the city's head of public protection and chair of SmokeFree Liverpool, said an adult rating on movies that depict smoking will reduce the number of young people lighting up.
"The international evidence...is that one in two children between 11 and 18 who witness smoking in movies actually experiment with - and therefore start - smoking themselves," Mr Hull said of recent research.
Liverpool already carries the unenviable title of lung cancer capital of England, with some of the highest smoking rates in the UK.
Mr Hull said Liverpool wants the British Board of Film Classification to act.
HAVE YOUR SAY
I thought we elected councils to provide services not become our moral guardians?
Russell James, Wirral
But a spokeswoman for the film board said smoking and alcohol use are already taken into consideration when a film is rated and a blanket 18 certificate for all smoking scenes is "heavy handed".
"To simply classify a film 18 because people smoke in it would not be popular with the public," the spokeswoman said, adding an extensive public consultation has already examined the issue to come up with existing guidelines.
For example, if a character popular with children such as Harry Potter was somehow promoting cigarettes or seen smoking, the film would be rated accordingly, she said.
"We would take that very seriously," she added.
Dr Stacey Anderson, of the UK Centre for Tobacco Control Studies, said the evidence of smoking's influence on young people is very clear.
"The more smoking a child views in films, the more likely they are to take up smoking," she said of the scientific evidence gathered in the United States and elsewhere.
Dr Anderson said characters do not even have to be smoking for there to be an adverse influence, just the sight of a pack of cigarettes or a tobacco advertisement has an effect on youth attitude.
She said if part of the role of the film board is to protect young people from potential harm, then smoking should be included in those considerations.
Mr Hull said if the BBFC is not prepared to adopt an 18 certificate then the city will consider using licensing laws to bring in its own stricter ratings for films screened locally.