Using clips from a range of films including Borat and Casino Royale, film examiners from the British Board of Film Classification explain how they take difficult decisions about which certificate to award a film.
The examiners say they reflect public opinion and, as public opinion changes, they respond with new guidelines. One of the trickiest decisions for the examiners is whether a film should be a 12A or a 15.
They look closely at the content of every scene. Four main issues determine the final classification - violence, sex and nudity, taste and decency, and bad language.
