Films and videos that appear to glamorise smoking or alcohol and drug abuse will face increased scrutiny under new guidelines announced by the British Board of Film Classification yesterday.

The BBFC said "greater weight" would be given to such depictions, which could affect the film's classification. The greater emphasis would apply only to films aimed at a young audience; scenes such as James Bond smoking a Cuban cigar in Die Another Day did not constitute a glamorisation of smoking.

The BBFC said changes to its classification guidelines would also lead it to pay greater attention to expletives with a racial association, language which offends vulnerable minorities, an emphasis on easily accessible weapons, and sexual violence and rape.

But the board ruled out big changes to its classification guidelines, which range from the universal U rating to the R18 category.

It claimed that a survey of more than 11,000 people last year had confirmed that audiences were generally happy with the system.

The president of the BBFC, Sir Quentin Thomas, said the public's attitudes to the classification guidelines had "been probed in some depth" by surveys and focus groups. The conclusion was that, for most people, the existing guidelines were "about right".

"The outcome [of the research] is that radical change is not needed," he said.

One area of concern was "slight confusion" among the public over the 12A classification, which states that "no one younger than 12 may see a 12A film in a cinema unless accompanied by an adult".

The BBFC said it would launch a public awareness campaign to explain the classification .

The BBFC said the focus groups had emphasised that context was an important consideration in the classification of films containing violence or sex and that it would try to be "less mechanistic" in its classifications.

Asked if the BBFC's research had detected any shift in public sensibilities, Sir Thomas said: "My own view is that the mood isn't becoming more permissive or censorious."

The revised guidelines would not lead to an increase in censorship or the number of films put into different categories from those sought by their distributors, he said.