Lights, camera, action! When we go to the cinema we sometimes experience scenes that reflect reality.

But does the imagery affect our behaviour?

A new study has found that teenagers who see actors smoking on screen are more likely to take it up.

5,000 15 year olds in the UK were questioned and many said seeing blockbuster films that depict smoking would encourage them to light up.

This research by Bristol University looked at the potential influence of some of the 360 top US box office films released between 2001 and 2005 that showed smoking, such as Spider-Man and The Matrix.

Now some experts are calling for a change in film certification so the under-18s are unable to see actors smoking on the silver screen.

Dr Andrea Waylen, who led the research, said "We saw a linear relationship between adolescent smoking and the number of films they had seen depicting smoking."

In the UK, films with ratings U (universal) or PG (parental guidance) ban scenes showing drug misuse but not cigarette smoking.

But is seeing the lead puffing on a cigarette really glamorising smoking?

If so, would the motion-picture industry have to re-think what goes in every scene from the start to the end credits?

Simon Clark, director of the smoker's group Forest, said: "We go to the cinema to escape from the nanny state… what next? Should government reclassify films that feature fat people as well in case they are bad role models?"